Windows 2000 Professional is literally unusable while burning a CD ROM, and during lots of other operations for reasons I cannot imagine. It takes actual minutes for my desktop to initialize after a reboot, and I usually have to reboot twice because MS Explorer crashes the first time, leaving me with no task bar. Part of the delay could be attributed to Norton Virus Guard. Whatever the problem, the performance is so horrible (on my 900 MHz Athlon system) that I cannot stand to sit around and wait for it. While I suppose I could get some reading done, I generally pop over to my Linux machine and get something done over there while Windows does whatever it has to do. Since upgrading to Windows XP and switching to a different security scanner, this problem has gone away completely.