sound and bluetooth drivers issues

hi, i have some problems with my sound driver, which is muted, and from time to time,
the sound come back by itself and then goes back to silence again, I already installed many dell drivers. or by microsoft updates and even restore to the factory point.
I don't know what to do with it. do you have any tips?

and second thing, my bluetooth option disappears; again, by itself, I went to the device manager, I didn't see anything there, and when I download the driver and install it,
the same thing happens, nothing changes in the device manager and in the control panel, where it is together with the mouse driver when it is recognized,
i also restore the w10 to factory mode, and nothing, i don't know if it's a bug, i don't know what else it could be. Any idea?

people at microsoft's support said that these are hardware problems, so they asked me to contact dell support, what could i do to solve this, my notebook is a inspiron 14'' 3421, bought in 2013.