Our installer generates a new GUID each time your do an install. This
was done so that if you install into a different directory on you hard
drive, it gets a new 'uninstaller' entry in the control panel.

I've written some logic that loops through all the keys of the uninstall
branch and returns the InstallLocation. If we find the same location
that was chosen this time, we grab the GUID for that install and I
update the %MYGUID% variable with the 'Found' GUID, however, I can't
seem to find where the correct place to place this code.

At what point is the installer writing the registry info and where is a
good place to put this type of code?

Thanks,
Ken