When I plug my ICOM 7300 USB cable into my computer port, "all" computer sound is muted even with the radio turned off. Everything used to work OK. The problem just unexpectedly showed up. Thinking that the problem was in the computer, I did an uninstall of the assigned COM port and also deleted and did fresh driver installation. Still no sound fix. After several trial and error attempts to fix the problem, I wondered if the problem was in the radio and not the computer. So, I connected the radio to a different computer and found there was no sound from this computer, either. Looks as if the radio has the fault and not the computer. Now, I am stumped about what to do. I am no digital expert so I am hoping someone has some good suggestions about what to do to fix the problem. I tried using FLdigi in the PSK-31 mode and found I can properly send and receive data to and from the radio using the radio USB port, but all computer sound is muted.