Have you checked the Event Logs? I would have a look through the System & Application logs, you can find these by running "eventvwr.msc" from the Run dialog box (Windows Key + R). Is your video card driver up-to-date? Could be something to check. Also, have you tried running your computer in Safe Mode, to see if this problem still occurs or not? To start Windows in Safe Mode, restart your computer and just after your BIOS splash screen disappears, start tapping the "F8" key on your keyboard. This should bring up the Windows Boot Manager where you can select "Safe Mode" by using your up and down arrow keys on your keyboard.