Sort of always the case.... just when you need something the most. Try an elevated command prompt and run the native System File Checker. Just type sfc /scannow and hit enter, just to see if there may be some windows corruption. It's kinda why I suggested a quick and dirty Linux distro boot above. There could be any number of things going on in Windows that might be causing some difficulties. Not the least of which might be some problem spots in the Windows Registry. Have you tried a restore point?