I upgraded my win from 7 ultimate to 8.1 pro and this happened.

I changed my OS from win 7 to win 8.1 pro and now i cant connect to internet. There isnt any errors. I cant find wifi adaptor in device manager. It has gone missing . Ot is either ethernet or local area connection. Help me? I need to update my graphic card. And also chrome gives an error DNS_PROBE_POSSIBLE . help.