Suspected GPU and PSU damage due to poor PSU

[Wingo]

My girlfriends computer recently blew up and I've been trying to work out why. I can say for certain problem number one was a nce blanket of dust and clogged fans. I cleaned them out for her before this particular problem occured, but I'm sure it contributed.

The main problem happened about a month or two after a grpahics card upgrade. It went from a FX5500 to a 7900gt. This was so the family could play games such as CoD4. What happened was the computer froze while playing and the screen was littered with artefacts. When trying to restart all of the post screens would have garbeled text and the XP logo would have artefacts on it. Their tech guy said that the graphics card had blown so he replaced it. Around the same time the PSU started playing up. Its safety would frequently flick during use turning the PC off. Now apprently the PSU was "fixed" but just recently it fried, sending smoke everywhere.

The system overall is fairly modest, pentium IV, basic mobo, 1 gig ram. What I am suspecting is the cause of these problems is with the new GPU the PC is drawing too much power from the PSU which is made worse during peak use. I'm sure the GPU was damaged due to poor power supply and the PSU fried due to too much power being drawn.

The tech guy told them that playing "all these ultra modern games" has damaged the pc. Now this is utter rubbish as playing a game doesn't damage anything in the PC, but I'm quite sure placing a high demand on a poorly powered set up would cause this damage. I've been trying to steer them away from this tech for a while now, he doens't seem to have a clue. They stick with him due to having "20 years experience", I don't think he has anything to show for it. He ahs designed two PCs for them and both had poorly configured fans which provided very little cooling and caused hard drive failures in one of the PCs. Also, when the GPU was replaced in the other PC it had that thick laer of dust inside. He replaced the GPU and left the dust lying there and sent the PC back to them. I would have thought a decent tech would clean out a PC before replacing anything to avoid problems.

To wrap up, how do I calculate the power required by the current set up to work out if the PSU was being overdrawn?

[Groundbound1]

I had a link for just such a purpose, but have long since lost it. I did a few google searches, and this is one that keeps coming up in the results.

http://www.extreme.outervision.com/psuc ... orlite.jsp

This will only give you a wattage estimate though, and nothing in terms of amperage.  Still, maybe it'll help?

[Wingo]

Thanks for the link. I've tested with a few CPUs from the P4 range (i'm not sure which they have) and it always comes back in the 500W+ range, and I doubt the PSU is that powerful, especially given the original PC desgin and age.

EDIT: With the same settings and the old GPU placed in the wattage drops to about 400w worst case scenario