Board Thread:Skyrim/@comment-107.222.8.146-20150709040501/@comment-6881629-20160112100445

As it's invisible in the inventory you have to use the console to equip it -

player.equipitem 000DEED8

Like i said if you really want the bow a mod would be better (like this you could equip it normally and it would be able to be upgraded and enchanted too).