Wifi problems after bios update

Hello.

I have a dell 3520: 6GB ram, 1TB hard drive, intel i5. A few months ago I had to update my bios... The problem became after I did it: At the very moment I started having issues with my wifi like it drops when I close the lid, and whenever I wake up the computer after it would take a looooooong time to wifi to start working, and actually, drivers disc won't detect the wifi card anymore. Moreover, the bluetooth doesn't work anymore. It doesn't shows up at all as installed in the devide manager.

I've been wondering if updating bios had something to do with it... So, I had thought to downgrade it to the previous version but then I came to find out that it is almost impossible (because I tried it and it was). So, any solutions to these?