computer starts sometimes, sometimes not!

[onewave4me]

just upgraded system to
msi ultra 2 kt333 w 2000+
512 m 2700
30g maxtor
10 g fugitsu
48x cdrw
56x reader
nvida geforce 4 mx
external modem
though most parts are those i had including case w 300w ps lately i have been haveing trouble starting my machine.

Just like its unplugged??? Sometimes it fires right up with no problems and will run normally for all day or sometime a couple of days then i will shut down normally and the next time i go to start it nothing.

I disconnect everything except vidio,ram and cpu sometimes it will fire and then i hook up the rest one at a time and it works great and runs well for a few days then after normal shut down it wont fire at all--no fans nothing-just Dead--Its frusterating and dont know what to check--suspecting PSU-no smell from it--do they die intermittly and then heal and work well and go out again??

What to check??? Any suggestions?? HELP

thanks for any replys

[PresterJohn]

yeah, your ps would be the first item to troubleshoot.

[Lemon]

When it does boot will it run stable? It might just be the switch on the case.

[onewave4me]

Yes when it boots it runs stable for days even in sandra burn in-- however last night on a normal shutdown every thing is good--this AM i go to boot and nothing--I have reseated everything .

Maybe it is the switch itself?? Next time it happens I will short the leads and see whats up..

thank you for the reply

[Kuasimodem]

300W power supply...

...what brand & model?

I've seen more than a few over rated power supplies that failed to even live up to their spec sheets, I've also seen power supplies like the Antec True 380 (rated at 380W output) go all the way up to 471W before it shut down, with no adverse affects

AMD processors require a good kick to get started, so make sure that your 300W power supply has a 5VSB (5V Standby) rating of at least 2.0A for consistent startups.