I got back to windows 7 64x
installed latest drivers
same problem i can't connect to both wireless internet and WiDi ..... even i didn't face this problem with windows 7 before
but this time the WiDi software in win 7 mintioned that the problem is "channel mismatch"
i forced the laptop using router settings to conect in 2.4Ghz mode not 5 then the problem was solved.
i'm wondering now if this solution will work for win8.1or not O_o ....
maybe when other win8.1 problems will be solved i'll try again on win 8.1 