Windows

I suppose that it has nothing to do with the sites that you visit or downloading software that is installed on your PC. Try this and see if it helps.

From another PC download and install these programs and copy the the installed folder along with VundoFix.exe to a USB Stick.

Restart the PC in Safe Mode and turn off System Restore insert the USB Stick and run Sophos.bat when it is completed run VundoFix.exe. When the PC reboots start in Safe Mode again and run Spybot.

Download Spybot - Search & Destroy 1.5.2 and install it. Update it. http://www.safer-networking.org/en/download/index.html


Download Sophos and the latest IDE Files. Install it and extract the IDE files to the C:\SAV32CLI folder.
http://www.sophos.com/support/knowledgebase/article/13251.html

Copy and paste the below two lines into Notepad and save the file to the USB Stick as sophos.bat, it will scan and remove.

===============================
CD SAV32CLI
SAV32CLI -REMOVE -P=C:\REMOVLOG.TXT
===============================

VundoFix is a freeware removal tool for many of the known variants of Trojan.Vundo, Trojan.Conhook and other similar infections.

http://vundofix.atribune.org/

Double-click VundoFix.exe to run it.
Click the Scan for Vundo button.
Once it's finished scanning, click the Remove Vundo button.
You will receive a prompt asking if you want to remove the files, click YES
Once you click yes, your desktop will go blank as it starts removing Vundo.
When completed, it will prompt that it will reboot your computer, click OK.

Also download and install CCleaner to tidy up your Registry. Let it run through until there are no errors left.

http://www.ccleaner.com/download

The Sophos SAV32CLI folder can be safely deleted after it is copied to USB.

Try running this as well.
RootKit
http://technet.microsoft.com/en-us/sysinternals/bb897445.aspx

You need to install the OS and Software again but this time you need to Wipe the HDD with a Utility that Writes Zero's to every Sector. When you reinstalled last time you may have made the system unable to see and do anything about the root problem here and it is unable to remove the cause and is only treating the Symptom.

Anyway even if you Formatted the Drive on the last install the System only writes to every third Sector and leaves the other 2/3 of the drive alone allowing the infect to reoccur. If this is the case you need to totally wipe the HDD with something like Boot & Nuke available free from here

http://tinyurl.com/4rfur

I hope you have a recent solid working Backup as you may have lost your Data already depending on what it is that this computer has caught by Unsafe Web Browsing If you can access your Data try backing it up to something that can be disposed of without any real cost like a Blank DVD Disc/s. If the Data is infected or corrupt you may need to throw the Copy that you make now to prevent it corrupting another install that is if you can even access it.

Col