Sounds erupts during recording live music

[rockinRon]

I have been using 1.2.6 for a few months now with some great success with recording some original music I am recording and just recently every time I go to record a track, the program records for a few seconds and then the monitor goes out briefly (about 1 second) and then is deafeningly loud and distorted and the recording track continues without recording. It can be painful! Additionally, when I go to preset the mic level prior to recording, it takes multiple attempts and it works for a few seconds and then locks up. I checked the Windows audio mixer and all my audio hook ups in my XP operating system and they are fine with every other music/audio program. I also checked my USB cord and it seems to be OK as well. What should I do? unistall/reinstall Audacity? I don't want to unistall for fear of losing what I have recorded. I do have some copied to disc, but others are still in process and I would hate to lose them. Do you have any insights??
The essentials of my system are 80MB hard drive, Centrino processor, Windows XP, 1GB RAM. I am confident that I have plenty of space to handle my project, but if you have better information, please let me know.