I just bought a new laptop with windows 7. I teach music and use my computer through windows media player to play music that has "split" channels. The vocals are on one side (Left) and instruments on the other (right). On my old Vista maching I always used the balance control and had no problem controling the balance to turn off the vocals once the class was comfortable with them and play only the instrument parts. I copied my music files to my new windows 7 laptop and the music tracks that work fine on my VISTA machine seem to run in "mono" on my windows 7 machine on windows media player. When I lower the right or left channel to 0 I still hear both channels as if it is in mono. Does anyone have any insight into this problem?
First thing I would check is the physical connection, sometimes minijacks can vary in manufacture and not fit correctly in some sockets, thereby bridging left and right channels.
Try a set of headphones and see if it makes any difference, if still mono try moving the jack slightly in and out with the headphones on, if you get seperation, you know where the problem is.
Apart from that, could be drivers, check for updates.
No guarenties, just suggestions, good luck.