Hello, I think your problem is related to your motherboard, first update your BIOS to the latest version and set it to it’s default configuration, if that doesn’t work then remove your graphic card and use your pc only with intel HD graphics, this will maybe fix the problem but will prevent you of gaming, if your computer works fine without GPU then the issue will be located in the PCI-E lanes, in the meantime try another PCI slot or much better another motherboard.
Note: do not overclock anything, leave everything in it’s default configuration.