Subwoofer in home theater system won't power on after moving?

[mentalfission]

So I have an RCA home theater system I pulled out of my own place and am now just using it as a stereo in my garage for my mp3 player. I have connected all of the wires but cannot get the subwoofer to power on. I connected the speaker wires from the sub to the correct terminals on the receiver but have 1 more wire, red and black (can be pulled apart) about 2 feet long hanging out of the back of the sub. There are no more terminals to connect them to but I am wondering, could it be possible my sub has to be powered and I ripped the plug out when moving? I don't see myself being that careless but what else could it be for? I didn't set it up the first time so I honestly don't know if it was ever plugged into the wall. It is not a high end system with a power hungry subwoofer, so would it need external power? What could be my problem?