[cetkat]

I suggest you read this and install the Windows updates:
http://www.blackviper.com/AskBV/tech10.htm

Then complete the steps in the link below and post the requested information in the HijackThis Forum, and see what they can do.

IMPORTANT - Read This Before Posting For Malware Removal Help

There's also this HijackThis thread that has the same kind of problem (yet doesn't seem to be the result of malware) that you can follow.