System Hangs on a Vista

[Hidden2147]

My computer is a Dell XPS 420. I am running on a Windows Vista Operating System. Recently I have been experiencing system hangs. My computer would just hang randomly with a black or grey screen. Can anyone help me out?

 

[gwb56]

Does it hang at startup or at shutdown times? Garry

 

[Hidden2147]

Does it hang at startup or at shutdown times? Garry

At random times when I'm using the computer or while playing games..