Press and keep tapping F8 when the computer is starting.
Choose safe mode.
Start > Run > Type:
Then click advanced > Settings (Third one) > Remove the tick from Automatically Restart > Click ok.
Let it boot into windows. Next time the computer shuts down you'll see a blue screen. Write down all the information. Post back and we'll see what we can do form their.
When your in Normal Windows (as above) but click, Hardware > Device Manager > Are there and ! marks?
Also scan for a virus.