Hello. I installed win 7 64 bit and after i installed my Amd Radeon Hd 5450 driver. The error came that Windows cannot identify the digital signature of the driver. So I searched for fixes but none of them worked . Then i reinstalled win 7 32bit and the error vanished . But for playing latest games like Call Of Duty ghosts I need a 64 bit os. So Please tell me how to fix this