When I installed Catalyst 13.2 beta 7 everything worked fine because it installed the AMD APP SDK Runtime. My problems started when I downgraded to Catalyst 13.1 .
Not sure what went wrong but these were the symptoms:
1) Could not mine bitcoins (Device detection flat out failed, not even showing any available devices)
Reaper.exe would show no Devices and quit out without any error message.
CGminer would show no devices and quit out without any error message.
GUIminer would attempt to start but quit out without any error message.
2) GPU-Z would start and say "ATI OpenCL driver bug detected, skipping OpenCL detection. Uninstall the AMDStream SDK/Open CL driver to re-enable this functionality."
1. Uninstall any AMD Stream SDK you have right now.
2. Delete amdocl.dll and opencl.dll from C:\windows\system32 and C:\windows\Syswow64.
3. Reinstall the AMD Stream SDK you have. Does not matter which one (I think)
4. Check to make sure the amdocl.dll and opencl.dll files you just deleted have not come back.
5. Check in C:\Program Files (x86)\AMD APP\bin\x86 and C:\Program Files (x86)\AMD APP\bin\x86_64 to make sure the files are there in that location instead. This is where they should be.
6. Try using GPU-z to see if there is a tickmark next to OpenCL. If there is, all should be well, and you can continue to use Reaper/CGminer/GUIMiner to mine bitcoins/litecoins/etc. Or any OpenCL program for that matter.
7. For some reason I had to delete the kernel files that reaper/cgminer had generated such as litecoin-reaperv13.Cayman-256-5760-2.bin but I am not sure that this was due to OpenCL because I tried unlocking my Radeon 6950 GPU to a 6970 (and succeeded, link here) So it may have just been that the number of shaders or something was wrong.
Stuff that didn't work
Removing the entire video drivers, reinstalling, even using Driver Sweeper. But Driver Sweeper doesn't know about OpenCL.
So I decided to just uninstall the AMD Stream SDK from the ATI Catalyst Install Manager in Add/Remove Programs. This fixed the GPU-Z errors but now GPU-Z had no check-mark next to OpenCL. The programs above had the exact same behavior. I tried installing old catalyst drivers, reinstalling new drivers, even downloading the developer version of the AMD-APP-SDK-v2.8-Windows-64 . They would all proceed to install files to C:\Program Files (x86)\AMD APP\bin\x86 and C:\Program Files (x86)\AMD APP\bin\x86_64.
This is where the OpenCL files are supposed to be located. I did a search for OpenCL and found some files in C:\windows\system32 and C:\windows\Syswow64.