How about unplugging one of the other window switches temporarily and swapping it over just to get your window to wind back up. It might be better than prodding around with a jumper wire.

First thing to try is the procedure suggested by LS. You can also try using an old screwdriver to connect the main power terminal (The one with the thick power cable going to the battery), to the solenoid terminal (usually has a spade connector on it). If you do this and the engine cranks it could indicate a fault in the wiring loom between your ignition switch and your solenoid. Be very careful not to touch the screwdriver between the supply terminal to any other metal surface on the car.