MS: A reboot from previous installation is pending on Exchange 2007

When you try to install a Exchange 2007 component like Management Tools, you will receive a message: A reboot from previous installation is pending. Please restart the system and rerun setup.

Solution:

1) Remove an orphaned UpdateExeVolatile registry key value

Navigate to HKLM\SOFTWARE\Microsoft\Updates\

In the right navigation pane, double-click the UpdateExeVolatile key and configure the key with a value of 0

2) Delete the orphaned PendingFileRenameOperations registry key

Navigate to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\, right-click the PendingFileRenameOperations key and select Delete.