Question PC won't output display and CPU fan won't spin

Jan 18, 2022
My issue is when I turn on my computer everything lights up and spins except for the CPU fan (confirmed to work except when plugging into the cpu_fan) and nothing comes up on my monitor. The motherboard displays LED codes 03 (not in the manual) as well as 15 (Northbridge initialization has started) and I think 18 (Southbridge initialization) but it is only displayed for a half second before showing the other codes.

My Specs (2012 build)
Intel i7 3770
Gigabyte Z77x-UD3H
GTX 670
Corsair vengeance 8GB CMZ8GX3M2A1600C9
Corsair TX750
1 x 128GB SSD
1 x 2TB HDD

Additional info: Leading up to this issue while gaming my PC would freeze for a couple seconds and I would hear a loud clicking sound that I was never able to determine the source of as it would only last a couple seconds. Thing I tried: using a different CMOS battery, booting while using every combination of RAM sticks, booting without the HDD connected, and I checked the CPU socket and a couple pins were bent that I was able to bend back pretty well (idk if I bent them taking it out or if it was already like that). None of these changed any symptoms at all.

I figure I am going to have to replace at least one part here just hopefully knowing which part to try first would be helpful. Thanks