Depends on what the problem is. You could have a break in one of the wires (happens alot with the cheap thin wires they use now days) of the main cord, that fix woould require either find the break and splicing it or just cutting and splicing in a whole new cord.
You could have a broken wire or solder in one of the speakers it self, that again would mean taking apart the unit and checking.
Your best bet is to check the warranty of the unit and see if you can send it back for repairs or replacement.
I assume you have already ruled out any other case, such as the PC being the issue?