Recently, I've been getting random dropouts (no sound at all) lasting a few seconds or more. They started infrequently, but are getting more frequent and longer in duration. It seems to happen when I hit bumps or go around curves. At first, I thought it must be my hard drive, but the vu meter and progress bar in Winamp suggest the audio is still playing; just not coming out. I unplugged the cable from my sound card, and plugged it into my mp3 player, and it sounded fine -- the problem is definitely with the PC. Also, my sound card is USB (Audio Advantage Roadie). I uninstalled this, enabled my on-board sound, and plugged the cable into the back of the PC. Unfortunately, this did not help at all. It also happens with any software playing MP3s, or listening to Sirius. The Sirius tuner shows full bars receiving a signal, so it is definitely in the sound.

What should I do next to try to troubleshoot this problem??? Is it possible for a hard drive to skip without affecting the software running; just the music output? And if it is the audio output, why would it also affect a USB sound card? I'm stumped!