Re: My computer wont start.
350 watts is plenty for a P4 unles you have some rediculous graphics card.
So the computer starts up normally but you get no screen? Can you hear the drive being accessed and reading? Is the CPU light blinking on as if it is being used?
If it turns on but nothing happens it probably isn't posting. If you have the spare parts you can swap them out to see what the issue is.
If you don't have spare parts purchase a little speaker that connects to your MB, then it should beep when you restart giving you an error code in beeps. Look that code up from th MB manufacturer and you'll know your faulty part.