All the above have provided good answers. For anyone stuck with a trojan that just
won't go away, I'd suggest you visit
Geeks to Go. Before you do, though, download Hijack This (just Google it - it's free and readily available) and run it; then start a new thread in the appropriate forum along with an explanation of your problem, and post the HJT log file.
I had a Trojan.Vundo and MS Juan Malware.Trace on my computer, and nothing would get rid of them. It was awful - every time I opened my browser, it would open two or three other windows. The first time I ran Malwarebytes, it found 20 infected files. No matter what I did, there were always two infected files. These guys finally fixed it. When you post a thread, one of their experts will work with you personally until the problem is resolved. Now my computer is as clean as it's ever been - and very well protected now (Goodbye, IE; it's Firefox w/ AdBlock from now on)).
Oh - and it's free, although they appreciate donations (who doesn't?).
BTW - I think I got the trojans from an 'imagevenue-type' site with a .cx domain name.
Just for future reference. Stay away from those Christmas Island domains. Should've known better from the goatse days!!!!!