Hi Kate.
I also need more info and am unsure about what you mean.
In the meantime here are some general tips about Audacity. Audacity is a stand alone sound file recording and editing program. It is not a media player......It uses the soundcard on your PC for record/playback.
If you are using the Audacity 1.3 beta version I suggest that you uninstall it and reinstall the 1.2 stable version. The beta version has known issues and is prone to crashing. The 1.2.6 version works well with Vista and 7. I have not had any probs and have ran it on XP and Vista,
Audacity should not be used with other programs running at the same time as this could cause problems especially if your PC has a low spec and memory.
Sometimes a simple PC reboot can sort out any probs that you may have. You may also want to check the Audacity I/O settings as the wrong options checked can cause crashes or loss of sound.