dont plug in another monitor lol :P
I've never heard of anything like this before. i wouldnt have thought it was anything to do with the connections to the computer! i dont know how the d-sub connector works exactly but i wouldnt have thought there was enough power there to knock out a monitor!
Id look at your power suppply first? check poweer cable, fuse, make sure its the right voltage (ie not a uk thing plugged into american socket)
these are shots in dark, someone who knows more about monitors please....