Video or PSU problem

My computer screen keeps going blank. It has done this several times and one time I got a VMM12... error. I searched and found that repairing the registry was working for people who've had that problem.
Even when booting from floppy, I still get this problem so I'm guessing it's the power supply. On the other hand I get the beep code that there is something wrong with the video card.

If I do need a power supply, I'm not sure what the motherboard and anything on it can handle. It is a MSI K7T Pro2-A and the psu currently in it is only 250W. I've got the manual but it isn't helping me right now.

 

What is your current video card? How long have you had it installed in your computer? I suggest removing the card and reinstalling it to make sure it's properly seated in the slot. And, while you've got the case open, clean out the dust if it's dirty.

 

I said it was mine but it's my mom's computer and I'm not sure what the card is exactly. It is an old SIS card (4MB-8MB card). It's been reseated and even cleaned.

Even if she does just need a new PSU, it's definitely time to upgrade the card.