Hi I strange problem with my motherboard lights on but nobodies home

[rppj33]

Hi I fitted a new graphics card to my sons PC - unfortunately after working for 30 minutes it died completely, nothing when I tried to reboot, no lights no fans etc. I couldn't smell anything burning so I swapped the PSU and stripped everything off the motherboard, now intermittently I can get the motherboard to fire back up but as soon as I reconnect anything it won't relaunch - any help or ideas ?

 

[popatim]

Please add the specs of the troublesome pc to your post which has been moved to the SYSTEMS section of the forums.
Thank you.