You are assuming a lot here. Over speed and the starter have nothing in common. EDIT: Thats not totally true. IF, the set shut down for an over speed event, the A2 will not let you start the set again, until you reset the A2. IF, the A2 is bad, it could be stuck in the Over Speed shut down mode, and it will not let you start the set. Lets try and solve these problems first.
Have you reset the A2, (Fault Indicator)?
If you haven't, then do so and try again. If you have, or you just did it and it brought no joy, pull the plug on the A2 and then try and start it.
Tell us what happens.