Monitor problem... big problem... please help...

[Demogorgon]

I'm running a computer from no brand in specific, self-made (by self I mean me, my friends, and a computer repair shop).
I left for a week with my pc turned off, when I turned it back on everything seemed to work fine minus the monitor. The monitor has power (yellow light is on) and when I push the monitor power button (only currently working one) the light turns green for a second, the screen reads "no input cable or disconnect" then flashes off real fast,and the green light turns yellow. When I first bought the monitor the screen would stay with the "no input" message if it was not connected to anything. I tried rebooting countless times and rewiring around my surge protector, no luck. Anyone have any idea how to fix it?
It's an AOC 21 inch monitor.