Where is a reliable registry key to find install location of Excel 2007?

Question

Where is a reliable registry key to find install location of Excel 2007?

Answer 1

I'm using the following key:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\excel.exe]

If the folder name contains Office12, you've got 2007. I'm using this method to decide during installation to install Office 2000-2003 addins or Office 2007 addins, as well as the folder to install them to.

This is extremely reliable, and also works well with localized versions of Windows. So far we've tested on French, German, Spanish and Italian with much better success than the other methods we were previously using. XLSTART should be the same in all languages, but be wary when developing word addins as "STARTUP" is localized in some cases.