It's nice that Microsoft included a basic defrag utility
in their follow-up to NT 4.0; however, you can't schedule
the defragmenter to run all by itself at certain intervals.
You can always upgrade to the professional
version for scheduling support, but now, there's no
need. Just download this util and add it to your Scheduled
Tasks in the Control Panel. This is an open-source program.
More information is availabe at the Developer's