Sounds like maybe you have a laptop with two GPUs, probably an Intel and an ATI.  I'm guessing Lenovo?

Anyhoo, see if you can completely disable the Intel on-board GPU and use only the discrete one.

After that I'd probably reinstall Catalyst 11.4 and see if it detects your card properly.

If I've guessed wrong, apologies.  Also, take care you don't overheat your laptop / burn out the tiny tiny fan.