The internet is both evil and my only hope.

We are coming to the end of day 3 of my computer-cleansing quest.  Yes, somehow the computer contracted a malady, and it is indeed a stubborn malady.  I started with a Norton virus scan.  Nothing was found.  I then went to a Microsoft virus scan.  Nothing.  And then I began an eight step process of scans, scans, and more scans.  Some malware was found, but so far the problem has not been fixed.  And the problem?  Invisible ads are playing in the background and the computer keeps randomly restarting.  The second issue has made it particularly difficult to get any of the aforementioned scans done, but I'm now on step 6 of an 8 step malware removal plan.  Apparently, starting the computer in safe mode makes it significantly less likely to randomly restart.  As I'm coming to the end of my eight step journey, I'm beginning to lose hope that the issue will ever be resolved.  Where do I turn next if I've employed ten different types of scans and have not found the root of the problem?  I'm open to suggestions and offers of assistance.