Here are a couple of links for background info/what other victims have experienced.(Chosen semi-randomly from a Google search)
MajorGeeks
Techsupportguy
Grisoft (AVG), in addition to the popular antivirus, make a dedicated antispyware, which comes as a free trial resident, then reverts to a demand scanner. Pretty good.
Emsi soft make Asquared trojan remover, free and pay versions. Also pretty good.
Other good ones are Superantispyware and SpywareTerminator (not to be confused with spyware x terminator.)
Give one or two of those a shot, might fix it.
You may need to download specialist tools, as the posters in the forum links have to, such as smitrem, to deal to it, and if the free programs don't remove it, it would be best to post to one of those forums for help. The instructions provided to one user aren't valid for another with a similar problem, unless you're lucky. Other good removal forums include Castlecops, which is good enough that it was seriously attacked by hackers/crackers and almost taken out a while ago, Scotts newsletter forums, and Piriform (ccleaner) forums.
The point about disabling system restore is as a final cleaning action, to be done at the end of the clean up once everything is ok. So anything hiding in there gets deleted and can't then re-invade the OS if system restore needs to be used in the future. It is simply turned off, then on again.