Outlook will not open-illegal operation

Whenever I try to open Outlook, the message that an illegal operation has occurred and the program will be shut down occurs. I have completely removed office from the computer and then reinstalled it. Until a couple of days ago, it was working fine. Now it will not open at all. Please help, this is on my boss’ computer. Also, when it happened, she said her computer had locked up and so she restarted it without shutting it down properly. Please, I need help.