We realy need a lot more information before we can help you. System specifications, OS used, AMD driver used, monitor used, how is the display connected to the GPU, etc.
Processor: Intel(R) Core(TM i5-2400 CPU @ 3.10GHz 3.30 Ghz
RAM: 8,00 GB
OS: Windows 7 64 bit
Driver: Catalyst software suite (15.7.1) (Legacy )
Monitor: Samsung 67.5kHz 60Hz PP 1920x1080 Connected with HDMI
All my games worked fine before but now textures are flickering in fullscreen to the point were some games are unplayable if not played in windowed.