When running AOL, Mark's mouse goes crazy, but when he goes to AOL via another web browser there is no issue.
Leo says that may not be a virus since it works fine from the web, It could be AOL's crappy software. It could be some sort of malware though, so it's smart for Mark to run his AVS and then run the Windows Malicious Software Removal Tool. Mark can also do an online scan from Eset, Housecall, etc. The problem with trying to fix it if he does have a virus, is that he could end up having more than one. There also may not be any restore points because they've been deleted, or they could have embedded themselves into the restore point itself. If he does have malware, the only sure way is to backup his data, format the drive, and reinstall Windows from a known, good source.