First off, I do not have much real experience with audio components. I can work on computers and other similar equipment, but audio I have never really tried.

My family just bought a new house and the living room is wired for surround sound. All the wires run through the wall. I have a Sony STR-DG520 and speakers. The problem is that none of the speaker wires are labeled. I don't even know which end is positive and negative (cables are all one color). I can't trace back where the wires are going since its running under floor boards, so I have to guess which wires go to which speaker.

Is there an easier way to do this besides trial and error? Will it mess my receiver and/or speakers up by trial and erroring it?

Yes, take a C or D sized battery after you install the speakers and you'll hear each speaker click when you apply the battery's + and - sides to the speaker wire. Also, the speaker will move outward with the proper polarity, +/-, and move inward with it out of phase. This will show you what is + and - for each wire set. Obviously, put some tape on each wire and mark it's location. If red/black, the wiring is obvious since most speakers will use this color code. If they are white/black, use the white for the red terminals.

. I don't even know which end is positive and negative (cables are all one color).

There aren't ANY markings? Sometimes they'll mark one of the wire pair with tiny numbers on one but not the other. I'd be surprised if there wasn't some marking somewhere.

There really isn't a "positive" or "negative" side to speaker wire. The electrons don't care as long as the positive connection on the receiver goes to the positive connection on the speaker.