Audio not working in unreal engine games


So, as it says in the title, every game made with unreal engine, that i have has no audio.
I am suspecting an audio .dll file, that i modified long time ago .
I wanted to reinstall windows 10 because of this, but i can’t, because i have so much work related programs, that have a certificate.
Is there any program or tool, that will allow me to repair dll files?
Thanks in advance for the answer!

If you modified an audio driver in your system you’ll be better off reinstalling / repairing your audio driver. This should resolve your problem. Just go to your device manager and look under Audio and repair your driver from there.