I've heard of that error on systems which were not fully updated or which were already infected with malware, as well as those having hardware problems (especially with defective memory). The first thing to do would be to insure that all Service Packs and critical Windows updates have been installed. In particular this update seems to be of some importance in correcting this issue: http://support.microsoft.com/kb/921883
Next, try checking your memory with one or both of the following tools:
Windows Memory Diagnostic http://oca.microsoft.com/en/windiag.asp
They are both free, and work extremely well.
If installing all of the latest service packs and updates doesn't help, and testing the memory doesn't find a problem, then I'd do a full malware check, and of course remove anything bad that you find. Let me know how it works out, Scott.