desktop problem

[WataShi12]

Hi, i'm new here.. I work as a teacher and at the same time i'm maintaining the school's computer lab. the school added 12 units of the same set up but one of which doesn't shut down properly. the CPU fan is on, as well as the power supply and the system fan. if i try to switch it on again, it doesn't boot up anymore.. i replaced the hard drive as well as the RAM. i talked to the technician from the store where i bought the computers but it seems he's just giving me "wild guess solution".. he said "maybe" the RAM is overheating, well i just replaced it, but it still the same.. If i leave it on for a while, it will normally work. but when you shut it down, there the 3 fans are still on.. im not sure if the motherboard is the problem or the power supply.. could anyone help me please? thanks. if all else fail, since the unit is still in warranty, i'll send it back to where we bought it.. thanks again..

by the way, here's the setup:

AMD Athlon X2 250 3.0Ghz

MSI NF725GM-P31

Kingston 2GB DD3

Seagate 500GB

Case with a PSU of 500W

the other 11 units has no problem at all, just this one.. They are all brand new, we just bought it last november, 2011. thanks

[Sp0iLedBrAt]

And have you looked at the temperatures and fan RPMs in BIOS? Is computer shutdown enabled at a certain temperature? It's also a good place to check the voltages of the PSU.

Cheers

[WataShi12]

And have you looked at the temperatures and fan RPMs in BIOS? Is computer shutdown enabled at a certain temperature? It's also a good place to check the voltages of the PSU.

Cheers

thanks sir, i'll try to check it tomorrow.. ^_^