Radeon hd 797 0issue

Hi evreyone I’m initiating to the joy of 3d rendering, and I got a little issue, Blender wont detect my radeon hd 7970, which should ( as i read somewhere else ) work at list in experminetal mode with opencl, the experimental mode being activated, still blender dosen’t detect my Radeon, How is that ? Has anyone a tip ( like editing in any way, a file in blender through the note pad or anything )

The issue is urgent because I’m working on a show that uses a lot of 3d rendering… So a lots of time waste while I’m stuck in CPU computation !