I got this strange behavior from my computer since a couple of weeks. and it began to happen just after i installed my brand new GeForce4 ti4200 (i had a matrox g450). Now it can suddenly shut down by itself !! And by shutdown i mean totally shutting downs, like if i pulled the power cord. To power it back up i had to use the switch near the PS fan ton turn it off then back on again. And now, sigh, after the 3rd power-out it doesnt come back on anymore :(
So is it the PS who is dead and could it be a case of overheating with the new video card ? maybe i should replace my PS with one with higner output (400W ?)... also it seemed to me that my system stayed up way more longer when i leaved the side panel of the case open.

thx for you advice guys...

---My specs
Athlon thunderbird 1200
leadtek geForce ti 4200 myVivo
cd-writer plextor
dvd-rom
one HD
Asus Mobo
lan card
256mb RAM

Jonny

Did you check to see if your motherboard is voltage compatible with the AGP card?
The newer versions of AGP use a different voltage to AGP1 and 2

i'll look into that.

My motherborad is an Asus A7A266 in case someone already know the answer.

I would say that if it will stay running for a while with the side cover off then you have a heat problem. Could be just an air flow problem and an extra case fan will fix it. Or could of been that the PS was over heating and going bad. You say it's dead now? Well anyway your going to need a new PS (400w would be good) before you can get up and running to check anything else. Once you get up and running again your going to have to keep an eye on your temps just to make sure that everything else is ok.

You can try robbing a PS out of an other computer to see if you can get the thing to boot and then check the CPU and MB temps.

Sounds familiar to me. The Ti4200 probably drained your ps if it was 350w or less, a 400w would be fine but I recommend a 500w (if your wallet is in agreement) to give a little elbow room especially if you are "upgrade-minded".... Your mobo should be fine, however I ran into a situation once where the mobo died as a result of overload.