Well the combination that I am using with my 5xxx GPU's is Catalyst 12.1 and SDK 2.5 with Win7 32bit.
Make sure you have all old AMD drivers completely uninstalled and removed.
Do a selective/Advanced install of 12.1 and DO NOT install the OpenCL SDK/Runtime 2.6+ that came with it.
Then install OpenCL SDK 2.5 then try running with stock clocks and see if it mines. If not then shut down and replace the card with one of your others and see if that works. Maybe you have a bad card(s)?
Sam
ok, thanks for the advice. ill do that now