there has been an issue with the latest version of Avast and a lot of Dell computers, many had to use safe mode to uninstall Avast. Should anyone have this problem uninstall AVAST then try doing a re-install they are working on the fix and it should be pushed out already. There may be other brands having the issue but most were Dell. If you have not updated AVAST to the latest VERSION you may want to hold off for a week or so, no big hurry the old version is still fine.

you do registry scans on a regular basis? well that explains a lot of why you have so many problems. It is NOT recommended to use registry cleaners ever. They are not needed and can cause serious problems with the system. I hope at least you have made backups of the registry before running a registry cleaner. Spybot is not the best tool either, it is ok as a back up but the scans you should be running are malwarebytes and superantispyware if you want the best options, both free. You should have seen us recommend use of those repeatedly. You definitely should have malwarebytes on your pc and update it and run it often since you have had problems in the past. Malwarebytes' Anti-Malware (Win) - Detecting and Removing Malware

have you tried a quick system restore to see if that would correct it? could be something got corrupted. Using Windows 7 or Vista System Restore

Could it be that these were previously "hidden files" that you chose to make visible? I think Avast does not scan hidden files. If no infection was shown, I would not be concerned about those that were not scanned. I'm sure you also scan with other programs that search for malware, so don't be overly concerned. Just my opinion, of course.