Computer won't boot

I was using my PC, when the screen blacked out. All the lights continued shining, fans spinning, etc.

I held down the power button to turn off my pc, then hit it again to turn it on.

However, the PC never boots up. It just turns on, the hard drive spins, and the screen remains black. My monitor IS receiving a signal of 640x480 resolution, but the mouse/keyboard lights flash on and off as if idle.

Help?

Edit: my monitor is plugged into my gpu via an HDMI cable. I have verified that the monitor is still working.

Edit2: my surge protector had failed. Plugging into a different outlet fixec my issue.