The issue isn't with Windows 8.1 because it doesn't handle that. The DHCP to get an IP is between the wireless driver and the router. I would go through this http://www.vindamedia.com/windows/help/troubleshooting-your-network
If you can get it on the internet with a Ethernet DISM /online /cleanup-image /restorehealth will work well. If not add /limitaccess to the end of that and use SFC/scannow.
Log out of your account and restart.