why dont you download and run the malicious software tool remover from microsoft? its always up to date.

Excellent advice, Vampy!

Also, check this out, Divya: LINK

And here: LINK 

Clean and reinstall.............that's the only way you'll be sure that your system is virus free.

Thanks for replies

I have checked it with Malwarebytes Anti-malware (with todays definitions) and Wnidows Malicious software removal tool. No infections found since I had restored from backup. However I can not install antivirus. I have mailed report to AVG.

Should I download another setup file or try another antivirus? But why I can't install that if system is clean.

  3L = ?    It's last alternative. 

I agree. Did you use the cleaning tool in the second link I posted?

Yes It detect no threats.

but how to uninstall it ?

Just had to log off and I could remove it.

Either it's there, or not.

Go to LINK and do the scan... Don't delete anything you are unsure of. You can save the report, and publish it here and email yrag and ask his opinion....he can be 'abrupt' so don't get upset.

Above all, Divya take is advice...or format. I hope you have a backup of your system BEFORE the infection.

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 7:46:34 PM, on 5/14/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\CyberLink\Shared Files\RichVideo.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\igfxtray.exe
C:\WINDOWS\system32\hkcmd.exe
C:\WINDOWS\system32\igfxpers.exe
C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe
C:\WINDOWS\system32\wscntfy.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Documents and Settings\vikesh\Desktop\HiJackThis.exe

O4 - HKLM\..\Run: [igfxtray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [igfxhkcmd] C:\WINDOWS\system32\hkcmd.exe
O4 - HKLM\..\Run: [igfxpers] C:\WINDOWS\system32\igfxpers.exe
O4 - HKLM\..\Run: [High Definition Audio Property Page Shortcut] CHDAudPropShortcut.exe
O4 - HKLM\..\Run: [NeroFilterCheck] C:\Program Files\Common Files\Ahead\Lib\NeroCheck.exe
O4 - HKLM\..\Run: [LanguageShortcut] "C:\Program Files\CyberLink\PowerDVD\Language\Language.exe"
O4 - HKLM\..\Run: [RemoteControl] "C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe"
O4 - HKLM\..\Run: [BluetoothAuthenticationAgent] rundll32.exe bthprops.cpl,,BluetoothAuthenticationAgent
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKCU\..\Run: [ccleaner] "C:\Program Files\CCleaner\ccleaner.exe" /AUTO
O4 - HKUS\S-1-5-19\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-19\..\RunOnce: [nlhr] RunDll32.exe %SystemRoot%\System32\AdvPack.Dll,LaunchINFSection %SystemRoot%\inf\nlite.inf,C (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-19\..\RunOnce: [tscuninstall] %systemroot%\system32\tscupgrd.exe (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-20\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'NETWORK SERVICE')
O4 - HKUS\S-1-5-18\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'Default user')
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_05\bin\npjpi150_05.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_05\bin\npjpi150_05.dll
O9 - Extra button: Encarta Search Bar - {B205A35E-1FC4-4CE3-818B-899DBBB3388C} - C:\Program Files\Common Files\Microsoft Shared\Encarta Search Bar\ENCSBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe

--
End of file - 3346 bytes

I had said...

So there shouldn't be anything in processes.

The installer got corrupt it couldn't be instslled on another pc too. I downloaded another Antivirus & installed without problems.

Could there be more corrupt files? How to stop them from being corrupt?