Vista - Mic only records on left side

This question was probably asked a million times already, but I can't seem to find a topic that has a concrete answer.

The built in microphone is fine, but whenever I try to use the front jack to record with my studio mic, it only records on the left side. It'll record from both sides in mono, but not in stereo, and I prefer stereo. When I put the noise reduction on in audio manager, it can be heard on both sides when I record in stereo, but it doesn't sound as good.

I've been using wavepad since it's a very simple program. On my other computer, which uses windows xp, it works fine in both stereo and mono and I don't even need to adjust anything in the settings.