FRAPS doesn't really give a lot of options. I have it set to 'detect best input' and it says stereo mix.
When that stopped working, I tried making it the default recording device and using 'use windows input' but that didn't work either.
Well I have the RealTek HD Audio Manager or whatever it's called and i've made sure the stereo mix isn't muted or anything, and I know for sure that the device is enabled.
Well this is embarassing. I did some more fiddling around with my speakers and things have started working properly again. >_>
Thanks anyway though, Astro.