Thanks Hydekar!
That a-search.biz problem was driving me nuts ! I like everyone else tried ad-aware, spybot, etc. I usually find that when I get these really tough spyware infections ad-aware and spybot are useless and only anti-virus programs work. Last time I had a tough spyware infection I used Norton's free online scan -- but that took forever.
This free little virus scan worked very quickly. I used the default settings (check for program files only) and it solved the a-search.biz problem. It was a trojan -- it found about 9 alltogether.
One of these trojans must be responsible for the a-search.biz problem, but I'm not sure which one. Here is my log from the virus scan:
File C:\WINDOWS\dllhlp.exe infected by "Trojan.Win32.Bizten.gen" Virus. Action Taken: File Deleted.
File C:\WINDOWS\telnet.exe infected by "TrojanDropper.Win32.Agent.k" Virus. Action Taken: File Deleted.
File C:\WINDOWS\zhelp.exe infected by "Trojan.Win32.StartPage.mw" Virus. Action Taken: File Deleted.
File C:\WINDOWS\loadnew.exe infected by "TrojanDownloader.Win32.Harnig.y" Virus. Action Taken: File Deleted.
File C:\WINDOWS\msxmidi.exe infected by "TrojanDownloader.Win32.Agent.dh" Virus. Action Taken: File Deleted.
File C:\WINDOWS\Q383305.com infected by "TrojanDropper.DOS.Rute" Virus. Action Taken: File Deleted.
File C:\WINDOWS\it.bat infected by "TrojanClicker.Win32.Qhost.a" Virus. Action Taken: File Deleted.
File C:\WINDOWS\s-orPE.exe infected by "Backdoor.Small.bb" Virus. Action Taken: File Renamed.
File C:\WINDOWS\System32\NETRUN.EXE infected by "TrojanDownloader.Win32.Small.qs" Virus. Action Taken: File Deleted.
File C:\WINDOWS\System32\telnet.exe infected by "TrojanDropper.Win32.Agent.k" Virus. Action Taken: File Deleted.
File C:\WINDOWS\System32\winmm64.exe infected by "TrojanDownloader.Win32.Small.vt" Virus. Action Taken: File Deleted.
File C:\WINDOWS\System32\s-s-nthh32.exe infected by "TrojanDropper.Win32.Small.kt" Virus. Action Taken: File Deleted.
File C:\WINDOWS\System32\wmsfake.exe infected by "TrojanDropper.Win32.Small.lq" Virus. Action Taken: File Deleted.
File C:\WINDOWS\System32\NAGCARDB.dll infected by "TrojanDownloader.Win32.Agent.bh" Virus. Action Taken: File to be deleted on reboot.
File C:\WINDOWS\System32\msfind.exe tagged as not-a-virus:RiskWare.PSWTool.PassView.151. No Action Taken.
Thanks again. If someone feels like trying to figure out which trojan exactly caused this a-search.biz problem it would be just a matter of removing it manually in the future (which is usually much quicker than doing a virus scan if you really don't need to do a whole scan).