hi guys,this is my first post and i wasn't sure where else to turn. i recently bought a new XFX AMD HD 7870 graphics card for my pc and it installed fine and everything and after about ten mins of gaming there was a loud crack and the pc turned off. When i turned it back on again, there was some sparks in the case and the whole house shorted. i do not know what to do, i have a (peak) 550W psu and a healthy fan that has worked for over a year with no problem. can anyone help? cheers, YarManYak ps. i have checked the capacitors and they are not blown and there is a strong smell of burning