In many cases all you need to do is remove the batteries and re-install them. Be sure your batteries have life and are usable. 

In some cases a re-zeroing solves the problem. To calibrate InfoCrank correctly:

1. Position crank arms at 12/6 o'clock (vertically) 

2. Ensure there is not load on crank arms 

3. Select calibrate/manual zero on bike computer 

4. Done ;)

In other cases a firmware update is required. If the battery reset above doesn't do the trick, follow out firmware link here for updates

If you've successfully installed the latest firmware and are still encountering problems. Email for Recovery Mode update instructions. They're a bit more complex.