My mac wont boot and loud fan

Hi,

I got new gigabyte nvidia card and tried to connect the power with the sata cable thru one of the hard drive slots. then the problem start loud fan no boot screen nothing.

when i removed the cable i saw the one of the teeth in the cable looks like got shocked.

Then i removed everything tried everything to make it work as usual, but its still doing as i said loud fan no boot. :(

help me pls