subcode,
ive never had a problem with it and i leave mine on for days at a time, in fact now that i think i about it ive never frozen up or lost anything, maybe you got ahold of some bad memory??? i dont know if that could be it but the only thing i can think of, or try booting with a different OS disk, i know those can become corrupt, cause i hada problem where if i used say disk 1 to boot up, my disk drive would keep trying to read the disk, but when booted with disk2 or 3 even i had no problems, luckly thats the only problem ive had so far.
anyways good luck