Are you sure that the Arctis 7's are charging correctly?
Do the Arctis 7 headsets work correctly on other computers?
More to do:
Right click the small speaker icon usually located in the lower right screen corner.
Check the Mixer and Playback device settings. May be something misconfigured therein.
Then check the other menu options.
You are likely to find many windows, tabs, and properties settings related to the headset.
Explore first and, when ready, change only one thing at a time.