Yeh, think i misread your first post... i thought it was a file you couldnt delete..
Have you had your HJT logs reviewed by one of the experts? if not, post them up, either in the malware forum, or if the moderator allowed it in this topic, in here....something you could pm them for...
If it doesnt come up in any scans - antivirus, ewido, it still could show its face in a HJT log... If that didnt show anything, you could always repair or redo your windows installation as a last resort... ( i know we should be able to work around it without having to do this)...
anyway post those logs and let us know..
Dave