I had similar problem because of an adware gah95on6.exe which was found on memory which you can find from Alt+Ctrl+Del report. It cannot be removed by spyware adware removal progams or antivirus software. Separate forum discussions are available at on the topic.
Sometimes simple things will solve the problem rather than diagnosing things in detail. As for this gah95on6 problem, first thing to do is to have a peep at the regular Add/Remove programs. If anything unrelated to our operation, business, should be deleted. For example, I have found a program called ShopAtHome which was throwing lot of critical objects at AdAware scans and probably the gah95on6.exe when it was removed with some password it provides, the file was not loaded in memory the critical objects number drastically went down.
Secondly if anything is in C:\temp folder we have to peep and remove.
Interesting thing is the only programme the above adware affected was FREECELL game which was creating problem. But once gah95on6 was removed FREECELL started working fine.
So we may look out for available simple solutions first