windows 8.1 wont recognize my graphic card

Yes they are conected the fans are spining but nothing happens. Got to run it through the on board graphic controller and when I go to device manager it only shows the intel graphic card is working. Yesterday I have changed the cpu from i5 2400 to i7 2600 it was working fine before then.
 


I am also having the same problem. 8.1 does not recognize my radeon..it is running but the only graphics card it is picking up is the motherboard. Does anyone have a solution to this problem.