Hello,
In order to better assist you could you please answer the following questions.
Which version of SignalVu-PC are you currently using?
Have you tried unplugging and reconnecting the RSA?
Are you connecting to a USB 3.0 port?
When you plugged the instrument in to the computer did it provide you with any error notifications?
Lastly, is your computer recognizing the RSA? You can check for it under the USB controllers tab in Device Manager.