For no reason, it just stopped working today. I spent 4 hours figuring out how to make it work again...
This is the combination that worked for me
1. Uninstall all AMD software expressly trough control panel
2. Reboot
3. Use driver sweeper (can be downloaded from guru3d)
4. Reboot
5. Download and install AMD SDK 2.6
6. Reboot
7. Download and install amd 13.4 driver
8. Reboot
It should work now...