It started after I upgraded my Nvidia drivers (my graphic card is an NVIDIA GeForce GTX 560), but also just after I updated windows. Sometimes, specially while using Firefox, my PC froze every few seconds, mouse turned slightly to weird colours (can't even describe it) and continued freezing until I couldn't do anything. Then it kept freezed BUT I could move my mouse. At this point I had no other option but to force shut-down and restart de computer.

I finally discovered that Hardware Acceleration on Firefox was apparently causing that problem, so I unchecked its box in the Firefox Options menu, and it solved the problem for some days. Now it has mysteriously come back, at random times. The computer might work fine for a couple of days but maybe freeze to death on the next day.

I then tried reinstalling Nvidia controllers, which I did without problems, but this still didin't fix any problem. For some reason I feel like Intel RST might be causing because after forcing shutdown and restarting, the PC runs extremelly slow until Intel RTS has opened, or uh... I don't really know. I have already scanned for viruses and I haven't found any threats.

I'm out of ideas and I'm certain that despite my PC works fine right now it might freeze again anytime. I need to know what's really causing these problems to begin with.