I tried playing Assassin's Creed: Brotherhood on my PC after I bought a new graphics card. The game used to run normally with the card I had before, but I'm experiencing graphics issues now - when I move the character around there is flickering in the sky area and around some of the light sources. The graphics card I played the game with before was an ATI Radeon HD 4850, and the new one is a Radeon HD 7770. The new card works normally in other games, so I assume it's a compatibility issue. Here's a link to my computer's DxDiag info file (I can't upload files to this forum for some reason): https://rapidshare.com/files/503978921/DxDiag.txt
All advice about how I can fix this is welcome!