usually a dns error, and or a persistant threat still there not on your computer...
sometimes fw's/anti-v will give you their dns or routes, and when you uninstall them it messes things up..
try to reset the router, reset your pc once that is done. and try again.
If that fails contact your isp.
If that fails, something went wrong with the drivers install, or the hardware has malfunctioned for some reason..