My problem.....Greyed out box on hardware acceleration on videostudio pro X5 where it used to be ticked in the past
.My solution....install old Nvidia drivers which were used at the time the tick was in the box...in my case...Geforce 314.22 driver.
Looks like updating drivers is not always the right thing to do?
My system....CPU Intel 980 ...GPU 680 GTX
I hope this trick helps others.