[LAU] New User

Hi all. I'm new here so I figured I'd introduce myself. I'm using fully upgraded Fedora Core 7 (Kernel 2.6.23.15-80) on a 2.4GHz Intel P4 in a Compaq which has a sound card integrated on the motherboard. lscpi reports it as being an 'Intel 82801DB/DBL/DBM AC'97 Audio Controller.' Which works fine. However, I dual boot XP, for which I sometimes have a USB I/O audio device (Alesis Multimix) connected. If I happen to forget to disconnect the mixer before I boot into Linux, the mixer is made the default audio device, and all reference to my internal sound card is removed. If I shut down, remove the USB mixer, and reboot, there is NO sound card available. If I run 'system-config-soundcard' I can get it to work again after clicking on 'autodetect', even though that is what it was already set at. Even then, Under the "PCM Devices" boxes, there are none available. Even without a PCM device available, I can play .wav files, so I guess I don't understand what the PCM output device does. Is there a way to prevent the mixer from being made the default (and only) audio device if I happen to mistakenly leave it connected? And what happened to my PCM devices? I searched fairly extensively, but all the things I found had to do with sound cards not working at all. Oddly enough, the mixer worked flawlessly under Linux the first time and was easier to configure than it was under XP. I just want the configuration to revert to the internal sound card after I unplug the mixer. Any help on this?? I've only been using Linux (this time) for about 5 months, and I guess I'm just not understanding what program is changing this, or why.