|Windows Installer Basics: Reboots|
Note that normally a user will be prompted for reboot if a file is in use and the user continued the install (or user wasn't prompted because Windows Installer couldn't work out which application name to display in the "FilesInUse" dialog). You can create custom actions to add to this dialog and you can see the "FilesInUse Dialog - Display if Program Running" section for an example.
Under Vista (Windows Installer version 4.0+) you should read up about "restart manager" and it's "MsiRMFilesInUse" dialog.
There are a number of reboot related properties:
Some standard actions you may wish to schedule:
Tools such as "PENDMOVES.EXE" can be useful to confirm things are going OK.