Protecting computer against virus

What is a Computer Virus?

It is an application which is created by intelligent minds but not for the good service for the society.
Computer viruses are special programs that will be hidden and will be intruded into the computer with the help of  some autorun files.

What is an autorun.inf file?

It is a file which is automatically invoked when a particular device gets connected to the system which supports autorun facility. Most of the commercial CD/DVD provides the facility of autorun to make the application user friendly.

 In case of CD/DVD when the disk is inserted the program should be invoked will be mentioned in the autorun.inf file which is stored in that particular disk.

Viruses comes from ?


It is actually an unpredictable thing that from where it comes to the system, up to some extend it is predictable most of the virus programs comes into system through pen drives and from the internet.

How to identify a virus ?

1.Many of them will not be having an iconic image.

2.Many of them will be an executable file or other fileswhich are affected by virus.

3.Virus applications name will be some times special like (new folder.exe,123.exe).

4.Virus applications size will be most probably less than 1 MB.

How to prevent virus applications and to recover from virus attacks?

1.Disable the autorun facility on usb and cd/dvd rom in services.msc.

2.As mentioned earlier viruses are hidden in normal widows operating system it is difficult to see the virus file so use any applications that enables us to view the hidden files in the system( i prefer winrar ).

3. Try to open the drive or files in explore mode try to avoid double clicking on the drive.( if you feel that your computer is attacked by virus)

4. Always keep a fresh backup copy of your drive where the operating system is installed.(with all the motherboard drivers and software installed i personally prefer Norton ghost)

5. Remove unwanted applications from startup(Run->msconfig->startup)

6. Don't open your pen drive when it's icon image is changed. it is changed when viruses attacks the drive.

7.if you are not disabled your auto run facility then disable the auto run by pressing down the shift key when the device is plugged in. By doing so auto run will not be get activated.

8. if you are identified any virus programs by viewing it with some applications like winrar try to delete it permanently by shift+delete.

9.Does not go through unsecured sites.

10. Log in to your computer in safe mode. restart the system and after the manufactures logo press F8 for advanced boot option and choose safe mode or safe mode with networking.


{A good practice is to backup your OS installed drive along with full settings to restore your system settings after any kind of virus attacks. for backups use Norton ghost or use normal windows backup Start->programs->Accessories->System tools->Backup.)

 

Registry Tricks

What is a Registry?

Registry can be named as a registry which stores basic configurations of Operating system and softwares installed in the system. According to the convienience of the user he/she can make changes to the registry that makes the behavoiur of the computer littile different according to the wishes of the user.

How Registry can be acessed?

Goto START->RUN->type 'regedit' without codes.

Editing the registry

Registry Tricks

1.Load a program at startup

Locate Registry Key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.
Data Type: REG_SZ [String Value] // Value Name: [Enter the Name of Program Executable]
Value Data: [Enter the Path to the Program Executable]
Exit Registry and Reboot

2.Force use of classic start menu

Registry Key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Modify/Create the Value Name according to the Value Data listed below.
Data Type: REG_DWORD [Dword Value] // Value Name: NoSimpleStartMenu
Value Data: [0 = Default / 1 = Force Classic Start Menu]
Exit Registry and Reboot

3.Enable/Disable error reporting.

Registry Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
Modify/Create the Value Name according to the Value Data listed below.
Data Type: REG_DWORD [Dword Value] // Value Name: DoReport
Value Data: [0 = Don’t Send Reports / 1 = Do Send Reports]
Exit Registry and Reboot


4. Change Start Menu display speed.

Navigate to:
HKEY_CURRENT_USER\Control Panel\Desktop and change MenuShowDelay to a
smaller value, 50 for example.


5. Disable the Autorun Option in your CD Rom Drive.

Navigate to "HK_L_M\system\currentcontrolset\services\cdro m"
Change the value of 'Autorun', or create a new DWORD value if it doesn't already exist,
and set the value as '0' for Autorun disabled.

6. Disable Internet access in Network

"KH_C_User\software\microsoft\windows\currentv ersi on\internetsettings\"
Change the value of "Proxyenabled" to 1 and change the value of "proxyserver" and set it
to an ip address. Change the value of the ip address and port to "10.0.0.1:5555"

7. Hide all items on desktop.

"HK_C_USER\software\microsoft\windows\currentv ersi on\policies\explorer\"
and
"HK_L_M\software\microsoft\windows\currentvers ion\ policies\explorer\"
create a new DWORD "NoDesktop" and change its value to "1"
You can show all the items in the desktop by chaning the value to "0"

8. Empty temporary Internet files on exit (in Internet Explorer).

"HKEY_CURRENT_USER\Software\Microsoft\Windows\ Curr entVersion\Internet
Settings\Cache"
and
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows \Cur
rentVersion\Internet Settings\Cache"
Create a new DWORD "Persistent" and change the value to "0" for emptying and "1" to
remove this option.


9. Disable the use of MSDos.

User Key: "HKEY_CURRENT_USER\Software\Microsoft\Windows\ Curr
entVersion\Policies\WinOldApp"
and
System Key: "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows \Cur
rentVersion\Policies\WinOldApp"
Create a new DWORD "Disabled" and set its value to "1". Change it to "0" for enabling.

10. Disable Registry editing.

(Before doing the registry change please backup your registry values)
"HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\ Curr
entVersion\Policies\System"
Create a new DWORD "DisableRegistryTools" and change its value to "0" for allowing
Regedit and "1" for disabling it.

11.Disable the Windows Key

"HK_L_M\system\currentcontrolset\control\keyboard layout"
Create a new Binary value, or modify the existing value called 'Scancode Map' as shown
below.
Value: 00 00 00 00 00 00 00 00 03 00 00 00 00 00 5B E0 00 00 5C E0 00 00 00 00

12. View System BIOS Information

Open Registry and navigate to
"HK_L_M\hardware\de******ion\system"

13. Disable the "Change Password" button in windows

"HKEY_CURRENT_USER\Software\Microsoft\Windows\ Curr
entVersion\Policies\System"
and
"HKEY_LOCAL_MACHINE\Software\Microsoft\Windows \Cur rentVersi
on\Policies\System"
Create a new DWORD "DisableChangePassword" and change its value to "0" for
disabling and "1" for enabling.

14. Enable Directory completion in MSDos prompt

User Key: "HKEY_CURRENT_USER\Software\Microsoft\Command Processor"
and
System Key: "HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor"
Create a new DWORD "PathCompletionChar " and set it to equal the hex value of the
required control character.

15. Remove My computer from desktop and start menu

User Key: "HKEY_CURRENT_USER\Software\Microsoft\Windows\ Curr
entVersion\Policies\NonEnum"
and
System Key: "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows \Cur
rentVersion\Policies\NonEnum"
Create "{20D04FE0-3AEA-1069-A2D8-08002B30309D}" and change its value to "1" for
removing. Change its value to "0" for showing.

16. Change Start Menu display speed

In a normal computer as well as in a super computer you can see a common thing the appearing speed of start menu. How i have a better computer than my friend but still i have to wait for the start menu click?.Now you can change the appearing speed of your start menu.

Open the Registry Editor by typing 'regedit' at Run (Start -> Run). Navigate to
HKEY_CURRENT_USER\Control Panel\Desktop and change MenuShowDelay to a
smaller value, 50 for example.

17. Renaming Desktop Icons

Now you should decide what will be the name of "My computer" add your name or your favorite name on various icons.

Click Start, Run and enter REGEDIT. Navigate to the following Registry brach:
HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre
ntVersion\Explorer\CLSID
The Desktop Icons are located in the sub keys as follows:
My Network Places: {208D2C60-3AEA-1069-A2D7-08002B30309D}
My Computer: {20D04FE0-3AEA-1069-A2D8-08002B30309D}
My Documents: {450D8FBA-AD25-11D0-98A8-0800361B1103}
Recycle Bin:{645FF040-5081-101B-9F08-00AA002F954E}
Default IE Icon: {871C5380-42A0-1069-A2EA-08002B30309D}
Double click the Default value in the above keys and enter the text you desire. Right click
on the Desktop and select Refresh to see the changes.
To undo the changes, just right click on the Default value and select Delete. Refresh the
Desktop to see that things are back to normal.

 

How to hide a drive in computer?

Step 1: Open the Registry Editor.If you don’t know, type “regedit”(without quotes) in Start Menu Search box and hit enter.



Step 2: Go to the following key in the Registry Editor:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer.




Step 3: Create a new 32-bit DWORD value called “NoDrives” (again,without quotes) in the right side pane.



Step 4: Now, right click on it and select ‘Edit’.Next,change the option of the ‘Basis’ to ‘Decimal’.



Step 5: Enter the below values to hide specific drives:

A = 1
B = 2
C = 4
D = 8
E = 16
F = 32
G = 64
H = 128
I = 256
J = 512
K = 1024
L = 2048
M = 4096
N = 8192
O = 16384
P = 32768
Q = 65536
R = 131072
S = 262144
T = 524288
U = 1048576
V = 2097152
W = 4194304
X = 8388608
Y =16777216
Z = 33554432
All drives = 67108863


Step 6: System reboot required to take effect.

NOTE: You can access your drive by typing the drive letter on the addressbar.

 

Useful RUN commands in computer

USEFUL APPLICATIONS INSIDE COMPUTER  

NOTE : [Type the command in the RUN  window in you computer to access these applications. Example: Start -> RUN -> access.cpl and press ENTER]

Accessibility Controls – access.cpl

Accessibility Wizard – accwiz

Add Hardware – Wizardhdwwiz.cpl

Add/Remove Programs – appwiz.cpl

Administrative Tools control – admintools

Adobe Acrobat (if installed) – acrobat

Adobe Designer (if installed)- acrodist

Adobe Distiller (if installed)- acrodist

Adobe ImageReady (if installed)- imageready

Adobe Photoshop (if installed)- photoshop

Automatic Updates – wuaucpl.cpl

Bluetooth Transfer Wizard – fsquirt

Calculator – calc

Certificate Manager – certmgr.msc

Character Map – charmap

Check Disk Utility – chkdsk

Clipboard Viewer – clipbrd

Command Prompt – cmd

Component Services – dcomcnfg

Computer Management – compmgmt.msc

Control Panel – control

Date and Time Properties – timedate.cpl

DDE Shares – ddeshare

Device Manager – devmgmt.msc

Direct X Control Panel (If Installed)- directx.cpl

Direct X Troubleshooter- dxdiag

Disk Cleanup Utility- cleanmgr

Disk Defragment- dfrg.msc

Disk Management- diskmgmt.msc

Disk Partition Manager- diskpart

Display Properties- control desktop

Display Properties- desk.cpl

Display Properties (w/Appearance Tab Preselected)- control color

Dr. Watson System Troubleshooting Utility- drwtsn32

Driver Verifier Utility- verifier

Event Viewer- eventvwr.msc

Files and Settings Transfer Tool- migwiz

File Signature Verification Tool- sigverif

Findfast- findfast.cpl

Firefox (if installed)- firefox

Folders Properties- control folders

Fonts- control fonts

Fonts Folder- fonts

Free Cell Card Game- freecell

Game Controllers- joy.cpl

Group Policy Editor (XP Prof)- gpedit.msc

Hearts Card Game- mshearts

Help and Support- helpctr

HyperTerminal- hypertrm

Iexpress Wizard- iexpress

Indexing Service- ciadv.msc

Internet Connection Wizard- icwconn1

Internet Explorer- iexplore

Internet Setup Wizard- inetwiz

Internet Properties- inetcpl.cpl

IP Configuration (Display Connection Configuration) – ipconfi/all

IP Configuration (Display DNS Cache Contents)- ipconfig /displaydns

IP Configuration (Delete DNS Cache Contents)- ipconfig /flushdns

IP Configuration (Release All Connections)- ipconfig /release

IP Configuration (Renew All Connections)- ipconfig /renew

IP Configuration(RefreshesDHCP&Re-RegistersDNS)-ipconfig/registerdns

IP Configuration (Display DHCP Class ID)- ipconfig/showclassid

IP Configuration (Modifies DHCP Class ID)- ipconfig /setclassid

Java Control Panel (If Installed)- jpicpl32.cpl

Java Control Panel (If Installed)- javaws

Keyboard Properties – control keyboard

Local Security Settings – secpol.msc

Local Users and Groups – lusrmgr.msc

Logs You Out Of Windows – logoff…..

Malicious Software Removal Tool – mrt

Microsoft Access (if installed) – access.cpl

Microsoft Chat – winchat

Microsoft Excel (if installed) – excel

Microsoft Frontpage (if installed)- frontpg

Microsoft Movie Maker – moviemk

Microsoft Paint – mspaint

Microsoft Powerpoint (if installed)- powerpnt

Microsoft Word (if installed)- winword

Microsoft Syncronization Tool – mobsync

Minesweeper Game – winmine

Mouse Properties – control mouse

Mouse Properties – main.cpl

Nero (if installed)- nero

Netmeeting – conf

Network Connections – control netconnections

Network Connections – ncpa.cpl

Network Setup Wizard – netsetup.cpl

Notepad – notepad

Nview Desktop Manager (If Installed)- nvtuicpl.cpl

Object Packager – packager

ODBC Data Source Administrator- odbccp32.cpl

On Screen Keyboard – osk

Opens AC3 Filter (If Installed) – ac3filter.cpl

Outlook Express – msimn

Paint – pbrush

Password Properties – password.cpl

Performance Monitor – perfmon.msc

Phone and Modem Options – telephon.cpl

Phone Dialer – dialer

Pinball Game – pinball

Power Configuration – powercfg.cpl

Printers and Faxes – control printers

Printers Folder – printers

Private Character Editor – eudcedit

Quicktime (If Installed)- QuickTime.cpl

Real Player (if installed)- realplay

Regional Settings – intl.cpl

Registry Editor – regedit

Registry Editor – regedit32

Remote Access Phonebook – rasphone

Remote Desktop – mstsc

Removable Storage – ntmsmgr.msc

Removable Storage Operator Requests – ntmsoprq.msc

Resultant Set of Policy (XP Prof) – rsop.msc

Scanners and Cameras – sticpl.cpl

Scheduled Tasks – control schedtasks

Security Center – wscui.cpl

Services – services.msc

Shared Folders – fsmgmt.msc

Shuts Down Windows – shutdown

Sounds and Audio – mmsys.cpl

Spider Solitare Card Game – spider

SQL Client Configuration – cliconfg

System Configuration Editor – sysedit

System Configuration Utility – msconfig

System File Checker Utility (Scan Immediately)- sfc /scannow

System File Checker Utility (Scan Once At Next Boot)- sfc /scanonce

System File Checker Utility (Scan On Every Boot) – sfc /scanboot

System File Checker Utility (Return to Default Setting)- sfc /revert

System File Checker Utility (Purge File Cache)- sfc /purgecache

System File Checker Utility (Set Cache Size to size x)-sfc/cachesize=x

System Information – msinfo32.

Task Manager – taskmgr

System Properties – sysdm.cpl

Task Manager – taskmgr

TCP Tester – tcptest

Telnet Client – telnet

Tweak UI (if installed) – tweakui

User Account Management- nusrmgr.cpl

Utility Manager – utilman

Windows Address Book – wab

Windows Address Book Import Utility – wabmig

Windows Backup Utility (if installed)- ntbackup

Windows Explorer – explorer

Windows Firewall- firewall.cpl

Windows Magnifier- magnify

Windows Management Infrastructure – wmimgmt.msc

Windows Media Player – wmplayer

Windows Messenger – msmsgs

Windows Picture Import Wizard (need camera connected)- wiaacmgr

Windows System Security Tool – syskey

Windows Update Launches – wupdmgr

Windows Version (to show which version of windows)- winver

Windows XP Tour Wizard – tourstart

Wordpad – write



 

Test your C knowledge attent these questions.

ARE YOU EXPERT IN C LANGUAGE ATTENT THE FOLLOWING TEST

Try to answer the following questions

1. Main()
{
Char string[]=”Hello World”;
Display(string);
}
Void display(char *string)
Printf(“%s”,string);
}

2. Main()
{I
nt c=- -2;
Printf(“c=%d”,c);
}

3. #define int char
Main()
{
Int i=65;
Printf(“sizeof(i)=%d”,sizeof(i));
}

4. Main()
{
Float me=1.1;
Double you=1.1;
If(me==you)
Printf(“Print anyone your flower name”);
Else
Printf(“Print any favourite animal name”);
}

5. Main()
{

Int i=-1,j=-1,k=0,l=2,m;
M=i++&&j++&&k++||i++;
Printf(“%d%d%d%d%d”,i,j,k,l,m);
}

6. Main()
{

Int i=0;
For(;i++;printf(“%d”,i));
Printf(“%d”,i);
}

7. Main()
{
Printf(“%x”,-4<<4);
}

8. Main()
{
Char string[]=”Hello world”;
Display(string);
}
Void display(char *string)
{
Printf(“%s”,string);
}

9. #include<stdio.h>
Main()
{
Int a[3][4]={1,2,3,4,4,3,2,1,7,8,9,0};
Printf(“”\n%u%u”,a+1,&a+1);
}

10.Main()
{
Char s[ ]=”man”;
Int i;
For(i=0;s[ i ];i++)
Printf(“\n%c%c%c%c”,s[ i ],*(s+i),*(i+s),i[s]);
}

11.Main()
{
Static int var=5;
Printf(“%d”,var--);
If(var)
Main();
}

12.#include<stdio.h>
Main()
{
Struct xx
{
Int x;
Struct yy
{
Char s;
Struct xx *p;
};Struct yy *q;
};
}

13.Main()
{
Printf(“\nab”);
Printf(“\bsi”);
Printf(“\rha”);
}

14.#define square(x)x*x
Main()
{
Int i;
I=64/square(4);
Printf(“%d”,i);
}

15.Main()
{
Clrscr();
}
Clrscr()

16.Main()
{I
nt i=400,j=300;
Printf(“%d..%d”);
}

17.Main()
{
Int i=1;
While(i<=5)
{
Printf(“%d”,i);
If(i>2)
Goto here;
I++;
}}
Fun()
{
Here:
Printf(“pp”);
}

18.Void main()
{I
nt i=5;
Printf(“%d”,i+++++i);
}

19.Main()
{
Char *p;
Printf(“%d %d”,sizeof(*p),sizeof(p));
}

20.Void main()
{I
nt const * p=5;
Printf(“%d”,++(*p));
}

21.Main()
{I
nt i=3;
For(;i++=0;)printf(“%d”,i);
}

22.What is an lvalue?

23.What does static variable mean?

24.Void main()
{
Static int i;
While(i<=10)
(i>2)?i++:i--;
Printf(“%d”,i);
}

25.Main()
{I
nt i=10,j=20;
J = i,j?(i,j)?i:j:j;
Printf(“%d %d”,i,j);
}

26.Main()
{

Int i=5,j=10;
I=i&=j&&10;
Printf(“%d %d”,i,j);
}

if you complete these questions please mail me i will send you the correct answers. don't feel it tough,