Virus bypassing scan & system32 files not able to be scanned

So it’s been almost a year I have this computer, and Avast! installed on it, and for a bit of time now, at the end of both short and deep scans, it says some files couldn’t be scanned.

Those files are situated deep inside the System32 folder, so I don’t know if it could be Windows files or just viruses.

As for my second issue, I just made a scan, and the pop-up window of Avast! says there is no viruses detected, though the original window depicts a virus alert…

I’m sorry if I did posted on the wrong category, but I hesitated between here and the Viruses and Worms tab.

How do I handle files that avast! can’t scan?
http://blog.avast.com/2014/02/28/how-do-i-handle-files-that-avast-cant-scan/

As for my second issue, I just made a scan, and the pop-up window of Avast! says there is no viruses detected, though the original window depicts a virus alert...
this has been reported by other users, may be a program bug ..... post a screenshot