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 http://www.vervecycling.com/firmware-updates/
If you've successfully installed the latest firmware and are still encountering problems. Email email@example.com for Recovery Mode update instructions. They're a bit more complex.