We’re runnning several PC’s (Win XP) with different MAX patches in a museum.
2 of these are linked to M-Audio Fast Track Ultra’s. After 2 years of running flawlessly, somehow MAX decided to switch to MME output rather than M-Audio ASIO output.
In a different project we had a similar thing with a MAYA44 USB; it somehow just decided to change it’s audio driver after a couple of months!
These computers run the same software day in, day out.
N.B. They do get switched off abrubtly, by disconnecting the power.
"Just" switching of the power on a modern OS can cause far more damage than you might realize. Which I think is most likely the cause for this behavior. If you want I can go technical on you (swap being written, open files, corrupt cache, etc.) but I think that’s not helping.
I’d advice to start with checking the disks (right click, properties, check for errors). After that see if those PC’s support power management. In XP it should be possible to make it cleanly shut down after you press the power button once (shortly).
But just turning them off is simply asking for problems to happens. As you noticed they might not appear at first but when they do it could be really bad.