After Windows service pack installation ot fix download, a lot of uninstall files and registry entries remains.
These files are needed for fix uninstall, but if the system stays stable, it is no more necessary.
These files are like $Ntuninstallxxxxxxx$ or $NtServicePack...$ in %systemroot%.
More information is here:
http://www.bellamyjc.org/fr/windows2000.html#Ntuninstall
with a VBS program to do that:
http://www.bellamyjc.org/download/vbs/deluninstall.vbs
Sorry, it is in French...
It will be another way to clean the machine...
Thanks,
Kriss