WiFi & Sound problem since Windows 10

Hello,

I have a Aspire V VN7-791G-7500 and recently did the Windows 10 update.

Since then, when i'm turning ON my laptop, I absolutely have to connect to the WiFi BEFORE entering windows (so, just before typing my password). If I login into windows without choosing the WiFi, it's impossible to connect to the WiFi afterwoods.

On top, even beeing connected, the WiFi is disconnecting by himself in a intermittent way. Sometimes often, sometimes very often. When it happends, impossible to connect anymore. Only solution is to reboot.

At the same time, the sound of windows is always showing a RED cross. When i click on the red cross, windows starts looking after the problem and resolve it.