Hi there,
There are a few steps you can take to troubleshoot your Soundbar.
You can download the firmware directly from Samsung’s website by clicking “Support” in the top right corner. Then go to “Manuals & Software” > “TVs & Home Theater” > “Home Theater” > “Sound Bars”. From there, you can select the HW-Q750C under Q Series.
Download the update and install it via USB thumb stick to your soundbar. If you need additional help, there are how-to instructions on this page. Please know that Samsung Customer Service is here to assist as well.
Next, try doing a soft reset, unplug the soundbar from the outlet for roughly 30 seconds and then plug it back in.
If this still does not correct your issue, then do a hard reset. With the Soundbar on, press the + & - Volume buttons on the body of the soundbar at the same time for at least 5 seconds. INIT OK” appears on the display and then the Soundbar is reset.
~Samsung Solutions