According to the latest silverlight deployment guide, I can determine what version of silverlight is installed by
-Querying the: “HKLM\Software\Microsoft\Silverlight\Version” registry key
This works great on my 32 bit dev machine. But on a couple of 64 bit machines, HKLM\Software\Microsoft\Silverlight doesn’t exist.
Where is it on x64 machines?
Look in HKLM\Software\Wow6432Node, the home for registry keys that 32-bit programs can see.