So the title says it all! I recieved a biostar tforce4 sli and put it together.... amd opteron 2core, 7800gt, 1g corsair ddr400(2-512 sicks). So i put the whole thing together and install windows, update the drivers and windows updates the a few hours later the thing crashes! No power! wont turn on for anything. When power supply on I get the LED_5SB which means that system is ready for power on, but the 2nd LED_DIMM wont come on. I thought it might be my power supply since I am using an old 430W 20pin but when I replaced it with a 650W-24pin antec still the same thing, no power.
Pull the mobo out of the case and plug everything in on a counter. You might be shorting the mobo to the case. If it works outside the case, youo'll need to do some serious inspecting to make sure you don't have an errant standoff still in the case.
Try resetting the CMOS. Couldn't hurt :wink: