Graphics Card Not Booting

[Arcanekitten]

hi so i was reassembling my pc and well everything worked fine but the video card not so i could really explain it but before i disassembled it it already showed some artifacts and when i reassembled the pc it dint boot up then i dint really know but i gave it a shot, i baked my video card at 200c with about 7 minutes i know not the best plan but if it already dint work then i don't have anything to lose.

after i baked the video card it dint boot then i tryed a other video card din't boot either so i was a bit confused so looked around and then i saw something what got me thinking maybe is PCI-e slot of my motherboard dead so i tryed another pc and it worked but....

then i thoughed i may be the intel hd graphics that took over the graphics which would explain why it dint boot in the other pc it had a amd video card in this one a intel so that may explain it but i wanted to check so i booted the pc up again then it said because it was a old pc and had windows xp on that i had to press CTRL+ALT+DELETE not that hard right?

well when i plugged in my usb my screen went black so i rebooted and another black screen then i unplugged the usb and tryed to boot it up AND IT GOT A BLANK SCREEN.

so right now i dont know how to fix it the video card that i baked and wanted to boot up is a HD7850 1GB from sapphire i used in the amd Phenom || x4 965 black and in the intel build a intel pentium or duo core there are two stickers on it and i wont boot up so cant look sorry ;/ the motherboard that i suspect has a broken PCi-E is a GIGABYTE 78LMT-USB3 in the amd build i used a CX430M power supply and in the intel a shitty one i dont even know the brand it gots a A-OPEN Z400-08FC if somebody can find out what maybe is wrong PLEASE answer also if anybody wants some information.