System freezing - Help

[Bezo]

For the last 2 days, my system has been freezing up. But not freezing where everything locks up. The session will continue to play, the mouse will move, but nothing works. I can't stop playback. I can't quit. I can't save. Nothing will work. And no error messages.

Sometimes it last for a few seconds, but sometimes it will last for a few minutes. Can anyone tell me what might be wrong? Maybe it's a coincidence, but this seemed to start happening shortly after I ran through Digi's recommended trouble shooting steps (except for unistalling PT or creating a new user). Could I have trashed something I shouldn't have?