Don't have a second monitor

It's really bothering me. My mouse gets lost on the second monitor I don't even have connected.

i don't know how to fix it. please help!

No. I did connect a second monitor on the first day I bought it, but I disconnected and never used it again.

I have one DVI which my monitor is connected to at the moment. I have 2 thunderbolts which have NOTHING connected to them.




Please see attached:

and if I actually connect a second monitor, it shows 3 monitors connected.

It's really annoying because some of the windows open in the invisible monitor and i can't even drag them over. I tried mirror too, no good.

Mac Pro mid 2012 running 10.8.5 with radeon 5770. 1 DVI, 2 thunderbolts outputs.

I just reseted PRAM (command-option-r-p right?), I didn't know what it was but it didn't fix the problem any way.