That is strange, but heres two basic things you can try right away.
Remove the GPU, go back to what you had. If you changed something on BIOS, I would clear CMOS as well. Install the drivers and check if its now working.
If not, considering that 7900XT is quite big but, basically every card is, inspect the onboard audio of your motherboard. You could've hit accidentally while installing the new card. Hope not.
Good luck
The Englishman