Opening PDFs from Outlook tries to use Excel

... but the current default program from anywhere other than Outlook is Adobe Reader.

Steps taken so far:

Repaired Office installation
Uninstalled/Re-Installed Adobe Reader
Used the "Open With" context menu to choose Adobe Reader and checked the box "Always use this program"
Attempted to remove the PDF entry from Folder Options and it wouldn't allow me
Edited the "Open With" registry entry for PDFs to remove the "Excel" option and change the MRUList to "a" only.

As it stands right now, Excel keeps returning to the "Open With" list, regardless of how many times I delete it. The registry is showing acrobat.exe as "a" and excel as "b", and the MRUList is "ab".

However, Outlook still defaults to Excel when opening PDFs. If I save the PDF to my desktop (or anywhere else for that matter), it opens with Adobe.

HELP!!! This is a brain twister...