This is from Sysmantec hope it helps...
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
Disable System Restore (Windows Me/XP).
Update the virus definitions.
Run a full system scan and delete all the files detected as Trojan.Adwaheck.
Delete the value that was added to the registry.
http://securityresponse.symantec.com/avcenter/venc/data/trojan.adwaheck.html
Apoc557
September 2005