My monitor doesn't detect tower and m/k, GPU, and case fan don'twork

Hey, so while I was playing a game on my pc , my pc decided to freeze up. Upon restarting my tower my monitor said "no signal" and my mouse and keyboard didn't light up like it should. So I opened up my tower case and noticed my case and gpu fan wasn't running. So I turned off my tower and switched out my GPU with an old GPU I had sitting In the closet and once I booted up the tower I noticed even this old GPU's fan wasn't running either!... (I didn't really think the case fan was a big deal but if it is. Let me know!) I tried the thing where you unplug the power cord and hold down the power button for 30sec and that didn't help at all... I also tried to clean the ram and switch the slot that didn't help either. I took out the CMOS battery for like 10min and placed it back in and of course didn't help.. I tried two different monitors same result. Is it the Motherboard or the GPU?

I NEED HELP! D: