I have a backup laptop that was running Windows Vista, but the hard drive crashed and I upgraded it to Windows 7 then to Windows 10. Big mistake. I immediately lost all sound and internet connectivity. After futzing around with it for a week and getting nowhere, I decided to use my main laptop (also running Vista) to search for solutions. Found a solution from a Microsoft employee: Win 10 was loading the wrong drivers for the laptop's Conextant sound system. He said to use the generic Microsoft audio driver that comes with Win 10. Same for internet LAN drivers. His solution worked perfectly and those functions returned.
Next problem I had was excessive battery drain. This was solved about a month later with one of Microsoft's updates. Battery consumption is normal now.
By default, Microsoft spys on everything and all those features that report your info to Microsoft is turned on. Be sure to immediately get into the Privacy Settings and turn all that crap to OFF. Some people have reported that even though they turned that stuff off, it had "mysteriously" turned it all back on. Well that happened to me about a month ago after a Microsoft update so I turned it all back off again.
A couple of other things to note:
Microsoft has set by default to "share" your Wi-Fi connection with anybody. Turn it OFF right away!
Windows Media Center is removed and all DVD playing capability is gone (no more watching DVDs on your computer). There are several free 3rd party software programs available to restore DVD playing to Windows 10 machines. I like the VLC Media Player and you can get it here:
http://www.videolan.org/vlc/index.htmlAll-in-all, I give Windows 10 a thumbs down. Stay with Win 7, it's still better. My backup laptop will stay on Win 10, but it's only going to be used once a month anyway just to keep the battery charged and get any updates.