Defrag wont run automatically from the msc.
In XP, you can run it from a command line, but that doesn't help you in Win2k.
You could set a batch file to send a message whenever you wanted to defrag, (ex. schedule a task to run a 'net send
%computername% Defrag me! at 4:55 p.m. every three months), or you could get a program that allows you to set up automatic defrags, but costs some money. I saw Raxco PerfectDisk, Defrag Commander, and Disk Keeper on google. You might check into those if you don't want the hassle.