Someone may be able to correct me on this, but older versions of windows (especially 2000) have horrible customization options for things like you're talking about.
My knowledge is limited, but im fairly certain that it requires professional versions of the OS, along with windows based scripting knowledge (for example, when i worked for FedEx ground, the tech manager for our Hub was able to manipulate windows in ways i've never thought possible"
But it was because FedEx had a certain version of windows, etc.
I guess my opinion is that you'll have to manually defrag each machine by using your own personal admin account on them.