Hey, I had a custom built computer which worked fine for years, but yesterday I replaced the motherboard and put in all in a new case. Unfortunately when I try to boot up the computer turns off, this sometimes happens after 3 seconds and sometimes after 30, it seems pretty random, if it stays on long enough I get the mobo screen and it starts posting about the hardware, that's the furthest it's gotten though, and yes I've reset the cmos . Any suggestions...
hi first off check for shorts, make sure the motherboard isn't touchin back of the case, this can cause it to randomly shut off.Also if you've installed an after market cooler if the base plate is metal make sure it isn't touchin any soldering on the back of the motherboard. You can rule out the power switch by shortin the two power switch pins on the control panel, if that doesn't work try another power supply unit.
sounds very much like the cpu is overheating, check for shorts first by reseating the board, then reseat the cpu heatsink with the right amount of thermal paste, if you have time check the system temps in bios. you can do this asap but if its a short its best to check for that first, then start working on the temp issues
