Are you using Garmin Express, or the ANT Agent and the Communicator Plugin? I'm guessing you're using Garmin Express...
Uninstall Garmin Express.
Download the ANT Agent and Communicator Plugin.
Install the ANT Agent.
Pair your device (enable pairing on your 310, and in the ANT Agent)
Install the Communicator Plugin.
Verify it works.
If you have Garmin Express, ANT Agent and the Communicator Plugin installed, just uninstall Garmin Express. You shouldn't have to pair your device again if you were using ANT Agent previously.