While poking around I noticed this file on some machines that was very large. 1gig i think....
%windir%\system32\wbem\logs\Framework.log
this is a file that holds errors and should only be 64Kb max. there is some bug in windows xp and server that sometimes makes it very large when using wmi it seems.
in any case, I suggest scanning for it in custom file scan and see if you find any large files you can free up. It may also indicate a problem if the service pack IS installed.