Build a PC No POST, error with PSU or motherboard?

A week ago i got a new CPU(AMD phenom x4 9750 95w) It was running at high temperatures under medium to low load (60c @30-50%) So i had purchased a new heatsink (corsair h50) to fix this issue. After a day or two under playing Bad Company 2 for a few hours my computer had shut off. I was able to boot up fine and figured it might be due to temps so i started to monitor them closer. Under full load (100% on occt) i wouldn't go above 50c.

Few days later while playing Bad company 2 it did it again. I thought it might be something with BC2 as it only shut off with this game. Next day shuts off while playing world of warcraft. I booted up and let it sit for a few hours before trying to play bad company 2 single player. This time when i turned on the computer it posted but didn't have time to fully boot before the power shut off again. tried booting again and my computer only turned on for a second. Now i cannot boot. I grabbed a PSU from a friend while i think it may not be powerful enough for my graphics card it will not post.
Taking out the card doesn't help either.

PSU i had was 500w
PSU i am borrowing is 450w

TLDR: Computer wont post on 500w (might be dead/dying) or 450w w/o graphics card

Question: Is my motherboard dead? Should i replace PSU as i replace Mobo? or mobo then psu?
 

klepto12

Posts: 1,116   +13
this really depends on the quality of the psu but imo the old psu could have damaged your MB but i would definitely try another psu first to make sure.
 
the 500w psu is ultra
the 450w psu is xion

I did try using the xion psu W/o my video card in and it didn't post.