Windows 7: Sound Problems- Stereo

Hi, Im having problems getting the sound to play on both of my speakers. I am hooked up to a reciever via a 3.5mm to RCA cable. ive tried plugging the RCA end of the cable into several ports in the back of the reciever, although Im only familiar with that being a problem when plugging into a phono port.
does anyone know if there is a setting within windows that i havent found that allows me to switch between stereo and mono?
Or do i need a different cable?
I had it plugged into an old sony stereo and i could get sound from both speakers, but only when turning the surround up. the surround sound knob acted as a volume control for only one speaker, with the master volume knob controlling both speakers.
weird huh?
not sure if this is a windows 7 problem or a hardware incompatibility issue.

the speaker just need a good old fashioned whoopin. a couple slaps on the top and sides and it works...