I had a previous version of Office installed on my computer and had CTRL + ALT + O be the shortcut to open Outlook (set by right clicking on the shortcut and choosing properties). Recently Office asked to update to 2016 which I did. In hind site I should have cleared out the shortcut before the update. Now that I'm updated to Office 2016 I can't set the same shortcut for Outlook because it's still tied to the old program. How can I clear out that combination so that I can reassign it again?