So many times I needed to install the SQL 2000 Server Tools and get the annoying message "A previous program installation created pending file operations on the installation machine. You must restart the computer before running setup." And what's puzzling you did not have a pending installation or maybe you did and it did not clear correctly.
Note that this is a registry fix so BACKUP before you attempt to make this change!
To fix this issue you will need to make a quick change to the registry.
Start run command prompt: Regedit
Go to registry area: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
Find the Key: PendingFileRenameOperations and delete this value.
If you are new to Regedit I would highly suggest that you backup the registry befor eyou perform this operation.
To backup the registry go to the Session Manager area and right-click over the "Session Manager Key" and click save.
More details can be found at Microsoft Support: KB Article 312995