I guess it's fair to say the monitor's probably fine. Since you said you tested a different monitor, did you test it with the same cables?
Is this a converter cable? I've had this once trying to convert my DVI-D to HMDI, or I might've just bought a broken cable, I'll never know, I won't put my monitor through that pain again. Or just test any of the other types available to your monitor/gpu.
What type of cable are you using? Are you able to test VGA if you're using HMDI/DP/DVI? I've seen this happen before with bad cables, or it might just be the input on the back of the machine.
