[andesj]

Every time I open IE I get ZA (zoneAlarm) telling me I have a virus (Trojan.Win32.BHO.abo) in file C:\\windows\system32\aclu.dll. When I try to remove it with ZA it just says error and closes.

[Elvandil]

It is probably in use. Find it and use one of these to delete it on boot.

Unlocker
Emco Move On Boot
UnlockIt
FreeFile

[andesj]

I have run all 4 program and rebooted every time, it's always there, (aclu.dll, and it's always detected by ZA.

[Elvandil]

Then it is probably being re-created by some malware. Scan with your anti-malware programs, scan with your anti-virus, try some other anti-malware apps because no single one gets them all, and/or post a log from HijackThis in the Malware forum for help from the experts.

Free anti-malware scanners:

Spybot S&D
Ad-Aware 2007
SuperAntiSpyware
Spyware Eliminator
Emco Malware Destroyer
Spyware Doctor
Arovax Anti-spyware
Trend-Micro Rootkit Buster
F-Secure Blacklight