trojan in my computer

hello
in my computer the kaspersky net security gives an aleart
that a trojan downloader win32 is trying to download a file from the site
[URL]:http:kgb.gbu12.info[/URL]
then it download a gameeeeee.pif file in the temporary internet folder
then some cab file like
1.cab
2.cab
3.cab
16.cab
etc
then a file is made in my C:\WINDOWS\system32 "system.exe"
& its corrupting my whole computer

i hav tried formatting with no help

i hav given the attachment [URL="http://virusinfo.info/attachment.php?attachmentid=83884&stc=1&d=1223678295"][COLOR=#0532aa]avptool_syscheck.zip[/COLOR][/URL] (34.7 KB)

plz help

You'd like to check your system in safe mode with CureIt - Tool. It's possibly a file infector.

[quote=Rene-gad;295789]You'd like to check your system in safe mode with CureIt - Tool. It's possibly a file infector.[/quote]

I have checked my system in safe mode with cureit - tool
found nothing
my Kaspersky is giving a warning that
[B]"Trojan-Downloader.Win32.Murlo.nn"[/B] is trying to download from
[url]:http:kgb.gbu12.info/gbu.gif[/url]

plz help

Clean Temp-Maps, Cache of Browsers, Recycler. Use Windows service tool [URL="http://support.microsoft.com/?scid=kb%3Ben-us%3B315246&x=17&y=6"]cleanmgr[/URL] or [URL="http://www.ccleaner.com/"]CCleaner[/URL] or [URL="http://www.clearprog.de/"]ClearProg[/URL]
Download [URL="http://www.download.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?part=dl-10804572&subj=dl&tag=button"]Malwarebytes Antimalware[/URL], make full scan and remove all finds.