Thank you to everyone who responded. Apparently, contrary to my previous statement, I AM an idiot. Thanks to silver1978 for pointing this out to me. It's partly a small change with Vista: with XP you double click on the speaker icon next to the clock; with Vista you right click on the speaker icon, and go to "Open Volume Mixer." On mine, there was a slide bar, which I hadn't previously noticed, and all the way to the right was a separate slider to control the volume for RP, which was, of course, muted. Hence why all the other audio on my computer worked, just not the audio for RP. Hope this helps anyone else who has the problem. And sorry for wasting your time.