Since all this happened after you repaired the bent pins on the CPU and the first PCIe slot on the Motherboard (normally the GPU Slot) is controlled by the CPU does indicate the CPU is damaged or one of the 4 pins may have broken after you installed it.
Best way to check the CPU is by installing it in another compatible Motherboard and see if the same thing occurs or not.
As mentioned physically inspect the Motherboard's CPU Socket for damage and CPU pins that your straightened out.