Hi, I have a problem with my Windows 7 PC and I have no idea what could be causing it, so I'm a bit worried if this problem is fixable? Anyway, what happens is that in random intervals (usually 10-40 minutes after booting) my Windows looks like it's "working", but instead if I press on any application option (like on a toolbar to save a notepad document, or in a browser to open a tab, etc.) or on the "X" button to close something, that said window becomes all whitish and freezes. All the other windows in the mean time are not freezed and they seem to be working, until I ALT+Tab to them, after which they too become whitish and freezed. Task Manager doesn't open at all, nor does the Ctrl-Alt-Del Welcome screen. The PC in question is not OC'ed, so it's not a temperature problem (plus it's very cold here at the moment). I scanned with NOD32 and did not find anything suspicious, and I also checked the Task Manager (before freezing) there weren'y any unusual processes there. That's what makes me so worried, I see no reason why this should be happening? Perhaps I can check Event Viewer for something specific, or??? The PC in question uses Windows 7 SP1 with all the latest updates.