Why does only one of my speakers work?

I recently got these new speakers and only one of the speakers is working. This happened about 3 weeks ago and i wiggled the wires in the back and it magically started working again. Today when i turned it on only one speaker was working so I messed with the wires and that didn't work. I went to the area that tells you information about the speakers and made sure that i have 100% volume coming out of each one. I know I didn't blow the speakers because I wasn't blaring my music yesterday and they were working fine. Also my speakers have a headphone jack into them so i plugged in my head phones into that and only one of the head phones works while plugged into that. I don't think there's anything wrong with my laptop but I have a hp with windows 7. Any suggestions?