If you are using a 2E or 2EW module, this is most likely a battery issue.  Make sure the batteries are charged.  You may want to acquire a "Rescue Kit" so you can run your equipment on a back up 9V battery for the time being.

It may also be a problem with the COM port or USB-to-serial adapter.  Make sure you are using the correct COM port.  You can use the Windows Control Panel / System / Hardware / Device Manager and expand the entry "ports" to see the correct port number.  You can also use the BrainMaster control panel View or Change Settings / Data Channels / Search this PC for Avaialable Com Ports to see which COM ports are currently available on your PC.

If you are using an Atlantis, it may also be a problem with the com port, or it may be something else.  Are the red lights flashing?  If not, contact BrainMaster.