Can't change theme, connect to internet, or update windows
I've recently rebuilt my system going from windows 8 to windows 7 ultimate. I had no problem installing or updating the OS, and it wasn't until about my third shutdown when it started having problems. When I started it up again, it was in classic theme. I can't change the theme back (all others are greyed out), can't connect to a network, I can't update windows. I've run full scans on Norton and malwarebytes, and neither found any malicious software. I don't know what to do because now I can't download or update anything to try to fix it because it won't let me connect to the internet.