Hi Tim,

a Shortcut is nothing more than a simple file with a .lnk extension. If you are 100% sure that the new Shortcut points to the new icon (and your issue is not caused by a "per-user" Shortcut problem; per-user and per-machine Shortcuts have different locations) then the old icon is still in the Windows cache. You can try the "Refresh Desktop" script function from within your installer. Or use "Delete File(s)" before you add the new Shortcut and "Refresh Desktop" after you added the new Shortcut. If this also does not help, you have a typical Windows cache issue.

Please see:

[more Shortcut related threads are available]

Hope this helps a bit.