@Sajainta: The term you want is "short", or, more formally, "short circuit", and for good reason.
You can think of electricity as basically running in loops--it goes out from the power source along a wire, passes through a bunch of stuff along the way, and then eventually returns to the opposite side of the same power source (that's why they're called "circuits"--it derives from the older meaning of "a closed path"). Electricity is basically lazy, though, so if you lay another wire across your big loopy circuit just outside the power source that allows it to jump directly to the other end of the circuit, it'll do that, leaving the main part of the circuit unpowered while it takes the shorter route--the short circuit--home.
If you have a desktop machine, you can just replace the monitor as Lord J said--old CRTs like the one I'm using right now can be obtained cheaply from any junk shop (if you insist on an LCD flatscreen, it's going to be more expensive--try pawn shops or computer stores that deal in used equipment). If it's a laptop, though, it's possible that D may be right about it being unsafe to run even with an external monitor--it depends on whether or not the short still gets power even with the built-in display powered off. (In theory, it should be possible to physically disconnect the display even on a laptop, but you'd need a wiring diagram and more electronics expertise than I have to do it safely.)
