best way to install when there maybe open files

[simulation]

Hi Guys,
I'm after a little advice on the best practice for installing files where one or more may be in use. The installer I am working on at the moment is an upgrade to an existing installation, so all the files are overwriting existing files (about 200 files in a couple of folders).

So, what I really want is to install the files, detect if any have failed to copy and if so, force a reboot so they can be copied at boot up time. i.e. combination of File /r and rename /REBOOTOK

Thanks in advance