It sounds like you will need to reinstall the OS. Yes, you will lose your connection to the BES. If you Desktop Manager is setup properly and you have an online connection to your email server (LAN, VPN, etc.) then Activation will start automatically. If it doesn't start then you can call your BES IT's and have them set up an OTA activation password. Once they give you a password you simply go to Options >Advanced Options >Enterprise Activation and enter your email address and the password they give you. Just tell them you need an Activation Password. They'll know.