If the N5001USB Auditor display has reset to show just a line and a box then the Auditor has reset.
This might not be a problem, for example you might have just changed the battery. In which case connect it as normal to the PC and download the program.
If however this has happened unexpectedly during use, then once is OK, but twice or more or repeated resets is unacceptable. In this case please return the unit for repair.