E6420 with Win10 problems

When I had Win10 on my E6420 I had such problems:

• keys for brightess didn't work, I had to restart or turn laptop into sleep mode and then wake it up to make the keys work again (keys didn't work when I turn on my laptop, I had to restart it to make them work)
• the boot time was very long. when I enter the password it takes long time to load all the startup programs,  when I got win7 it takes about 5 or 6seconds to load all programs, even skype, antivirus etc to load succesfully and then I can go. but on win10 i have to wait 15second till everything open, even skype is loading about 10second, in win7 i got it immediately, i dont know why does it take so long, unsupported graphic drivers or what??
• in devices I have 2 audio devices which are called the same hd audio device, and sometimes one of them is automatically turned off, when i try to uninstall one, then it is automatically installed again, but then still turned off (whats the point??)

I don't know if was it beacuse not supported drivers, bios, chipset or whatever. I want to know if it is fixed now or if it will be cuz when I upgrade to win10 I dont want to restore again to win7 in due to these problems.