need help computer wont post with video card in

[Wolfsraider]

my brothers computer got hit with a power surge we replaced the mother board, great now the board lights up but no video, I replaced it with mine, as I have onboard video. but I tried his card in mine, this is the effected computer, no go I tried a hd6870 no go it wont even post I have to remove the cards to get it to post, could I be missing a setting, I know it was finicky before when it comes to video, but the computer wont even attempt to power on, like its completely dead no lights whatsoever. is there something else I can try? I set the onboard off in bios and set to pci express prior to testing.

specs:
3.30 gigahertz Intel Core i5-2500K
ASRock Z68 Extreme3 Gen3
ati hd 7770 and ati hd6850 both tested and no video
Windows 7 Home Premium (x64) Service Pack 1 (build 7601)
SAMSUNG HD753LJ [Hard drive] (750.16 GB) -- drive 0, s/n S13UJ1MQ603835, rev 1AA01112, SMART Status: Healthy
SSD2SC120G3LC709B121-460P [Hard drive] (120.03 GB) -- drive 1, s/n PNY17140000494050030, rev 541ABBF0, SMART Status: Healthy
8 gb ram

This setup has been running nearly 3 years without issue.

I remember having issues getting the video off onboard when I got it and remember it not having power then too but cannot remember what fixed it lol any help appreciated

 

[Ketchup]

Maybe the motherboard got the power supply too. Enough power for onboard, but not enough on the 12v line for a dedicated card.

 

[Burpo]

Try clearing/resetting the BIOS (or remove cmos battery), then power up with only 1 video card & see if you have video.

 

[denis280]

Maybe the motherboard got the power supply too. Enough power for onboard, but not enough on the 12v line for a dedicated card.

+1

 

[Wolfsraider]

ty checking these out now sorry got hit with ot