I restarted my computer and it acted fine, shut down correctly but it started trying to restart 3 times then died. I've tried 3 different power cords, made sure my surge protector is functioning correctly, but it's not even getting power now.
It sounds like your PSU (power supply) or motherboard has died. If you have a spare PSU, try swapping it out. If you are good with electronics and a multitester, you can pull out the PSU and check the leads for the correct voltages.