Okay, so I've been running a Biostar TF570 motherboard and it won't turn on any more. To clarify: I don't mean it won't boot, I mean it just flat out won't do anything if I hit the power button. I doubt it's a PSU issue because when I hook up the appropriate cables to the mobo the LEDs that indicate it's got power are nice and yellowish green.
About two months or so ago a problem started up where the computer would power up fine but refuse to go through POST or display anything on the monitors. I found that cycling the power supply on then off would clear it up, but after awhile it took more and more cycles and/or resetting the BIOS (not sure how that helped, but it worked for some reason). Eventually I started removing and reinserting the SATA and power cables to my hard drives which somehow reset the BIOS (somehow I managed to forget my mobo's speaker is embedded into the front of my case - right next to the hard drives and that combined with removing/reinserting the cables managed to fool me into thinking it was a problem with my main hard drive the entire time.) I got home tonight and was going through the usual ritual of getting my machine to boot up when it just flat out died on me. One of the cycles I tried to turn the machine on and it just immediately shut itself back off and from there on out refused to power on no matter what I've tried.
I'm pretty sure the motherboard's destined for the scrapheap now, but on the off chance there's something I missed...
My rig's specs at the time of death were (to the best of my recollection):
AMD II Athlon x64 2.8 GHz dualcore
4x 1GB dual channel OCZ RAM
Nvidia 9800 GTX
ZEROtherm BTF80 CPU cooler
Two SATA hard drives of different makes.
I've also checked the mobo with a volt meter and I'm getting nothing from the two prongs where I plug the power on switch into (I've also checked the switch itself and I get a circuit once I depress it with the volt meter stuck into the plug itself.)
That will give an indication if the power supply is working, but won't test load.
Short the 2 power pins on the motherboard with a screwdriver momentarily to start it, in case you have a bad power switch.