In principle, everything is quite simple.
I like to play in windowed mode. Before, there were different graphics card, х1950, 2900, 4870, gt260, 5830, now a 6970. In fact, in windowed mode I sit since the 4870, usually played at a resolution of 1440*990, 1376*768, (At a total resolution 2960*1050) on a 6970 these permissions is missing. Left 1280*800 and 1280*960, immediately thereafter 1680*1050.
To bring back the resolution is very desirable, but the classical method described in the search (adding in the registry of supported resolutions for your video card) did not help. Maybe Hebraist help? )
UPD: Catalyst 10.12 driver 8.801-101125a-10989c-ATI