If your instrument is not communicating with the PC, a good first
step in identifying the issue is to do the following:
1. If available, replace the communications cable going from the
instrument to the PC and test connectivite by performing a calibration
of the instrument through the software.
2. If you have other instruments that connect to PC (with known working
com port), connect the instrument to that PC and perform a
calibration of the instrument through the software.