microsoft office not activating on new mac

I recently got a new MacBook Air and used the migration assistant to move all of my files and information. When I go to use microsoft word or excel, it won't let me save my edits, saying i need to "activate" my Microsoft office. When I go to log-on, the cursor just spins and it won't take me anywhere. Has anyone else had this issue? I really don't want to have to purchase Office again.