I installed Ubuntu 11.10, then turned it into XFCE. It works, but sometimes the audio will stop working, requiring a reboot to fix it. This will happen in the middle of a video, played using vlc. I'm on a Dell Latitude E6400. This never happened on a straight Ubuntu distro in almost 2 years of use, so I'm pretty sure it's not the hardware.
What do I do to diagnose this problem when it happens again?