My computer cut out one day (all the lights, etc were still on, but no activity) I replaced the power supply, but now it starts up for about 5 seconds and then shuts off. . .any ideas?

I've checked all the connections, nothing seems to be 'fried', so any input will be greatly appreciated.
Thx in advance.

Did it behave the same with old PSU? Can you list your configuration (and old and new PSU's wattage)?

no, with the old psu it wouldnt fire up at all. there was a little led light on the motherboard that was on. . .thats about it.
the dead psu was a 300 (tested w/ another 300 psu from the machine i'm posting this, and i got the same issues as the new one, which is 350 watt)

it's an amd2400 processor on an asus motherboard.(A7N8X-X)
1.25g ddr400 memory (3 sticks)
nvidia fx5600xt vid card


Again, one day i noticed the light on the front of the machine was on, but the usual humming of the system was missing. I hit the pwr button, and the lights went out. .but in trying to restart it, nothing happend.

Replacing the PSU yielded favorable results, however around the time I should be hearing the 'magical' beep just before initializing, it shuts down. I dont see any damage, and i've troubleshot various components (trying 1 stick of ram at a time, etc. .) and I still cant get it to stay on.

300 w is way too weak for the machine like that. 350 w barely makes some sense. You should find PSU 450 w or more to test.
No wonder 300 w fryed. It was giving 110 % all the time.

Lack of power might done some damage to the system. CPU's most wournable there for it recives 2 or more different voltages. If any of those voltages went up (in the moment of PSU frying) be sure it is FUBAR.

so if it did fry the cpu, ( i looked at it, and nothing was physically wrong w/ it) could the motherboard be screwed as well?

Yes, but usually the CPU is first to go. They both can be fryed. And it takes 1.5 V to fry the CPU, so it won't be anything visible to the naked eye.

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