Is this only when you do a restart through the Shutdown menu, or when you turn on the computer from a cold start? Check the Event logs as well for any possible errors.
Go through this list as a start to try and figure out:
- have you recently installed any new software?
- have you recently removed any software?
- do you have more than one antivirus or firewall running at the same time? If so, disable one of them.
- if you have any realtime protection for your anti-spyware app, try disabling it, then rebooting - does the error go away? If you have SpySweeper installed, try disabling the shields, one at a time, to find the culprit.
- have you gone to Windows Update to get all the required patches?
- have you recently updated any drivers or added new hardware (like a printer or camera)?
When did this error begin to occur? Try and find an error message or code and post it in this thread. You may also want to try Safe Mode with step by step confirmation.