>Sad news. The program has been installed on several hundred machines over the last couple of months. Too late to change the install.

If you provoded uninstall than you may still have a chance. You can run install on a test machine and use RegMon tool from http://www.sysinternals.com/utilities/regmon.html to see what registry entries are created.

>Is there any way to read values from the Start Menu, since the install will have put an entry in there that points at the directory?

If you can use WSH

oShell = CREATEOBJECT('WScript.Shell')
lcFolder = oShell.SpecialFolders("Programs")
*lcFolder = oShell.SpecialFolders("AllUsersPrograms")
lcShortcut = "Internet Explorer.lnk"

IF FILE(ADDBS(lcFolder) + lcShortcut)
	oShortcut = oShell.CreateShortcut(ADDBS(lcFolder) + lcShortcut)
	? oShortcut.TargetPath
ELSE
        * Shortcut not found
ENDIF