The popular black screen at start-up *Please help*

I am trying to fix my mother’s 8 year old Desktop. When i start it up, it goes to the screen that says ‘Windows didn’t start properly’ and gives me options on how to start. ie. safe mode, etc. Problem is, whatever i choose (inc. safe mode) i still end up with the cursor and a blank screen. When it used to work, it never shut down properly, it always got stuck in the “Windows shutting down” blue screen but will stay there all day until i force the off button. Please help!! Are these symtpoms of a virus or hardware malfunction? considering how old the machine is. The windows version is XP. Thanks!!