hi Nick,
there is a fix for this problem (Tech ID # 263295) which suggests re-registering the SCHEDMGRUR.DLL file. If it doesn't work, try below.
The fix for the Add/Remove programs problem is under article number 266668 in the Microsoft Support Knowledge Base. This suggests re-registering the APPWIZ.CPL control panel applet, but this did not work in our case, so we ran the in-place Windows 2000 upgrade (step 5 of the article) :
a) Run winnt32.exe from the \i386 directory on the Windows 2000 CD-ROM
b) When the Windows 2000 setup screen appears, select "Upgrade to Windows 2000"
c) Allow the installation to complete.
You may need to have your network card drivers handy, as we were prompted for the location of these.
Harry