Audio Playback cuts off randomly. Please help.

I have never experienced this before but in the middle of recording and playback I'll here a click and then everything becomes silent. I still have level and Pro Tools still records my audio but I hear nothing. When I close the session and restart I hear a click again and suddenly I can hear. But after a few minutes I hear this click noise again and then no audio. The click sounds like I had a track record enabled and then just plug in the instrument. But of course that's not the problem because I had my instruments plugged in the whole time. I'm currently recording a song with just a bass and guitar using Guitar Rig as my effect for both. Has anyone had this problem before and does anyone know how I can go about solving the problem. Thanks in advance.

I'm having the exact same problem right now. Can anyone help? I tried deleting the Digidesign Databases folder, and the DAE prefs folder, but the problem persists. I also tried creating a new session an importing everything, but still the same result. I'm on 7.1, XP, w/ a DIGI 002.

Are you listening back at high levels? Do you still have a signal on your headphone jack? Sounds like you're overloading your playback system and your protection device is switching off.

Thanks for the replies. To clarify, the Pro Tools software stops out putting signal. The individual tracks continue to play (as evidenced by the meters moving), but the master fader displays no audio output (nothing on the meter). So to answer your question there is no audio coming out of the headphone output, Analog Outputs 1-2, or the monitor outputs. Perhaps I'll try sending something to the analog 3-4 outputs and see what happens. I thought perhaps the CPU was being overloaded, so I set the buffer at 1024, and bypassed all my virtual instruments, but again, the problem persists. Sigh. :(