it would much helps if you attach with dump files.

1. reset your mobo cmos settings
2. clean all the existing ATI driver and software
3. install the driver from manufacturer CD.
4. test run again.

hmm, you can go to bios there and set to default factory settings.
btw, you already done the 2nd and 3rd step so just test the result any error again or not if not then you can skip the 1st step.

then try diff version of GC driver, if manufacturer driver having problem then go to ATI download the latest driver. for GC setting just left it default.

mind to show us your laptop temperature?

after do some research in Google still can't found any good answer, the last resort for you i think is update the bios probably.
if happens again you better just send it for warranty.

are you sure you update the correct version?
try to remove battery and power plug then wait for a while then connect it back.

*laptop still new just send for 1 to 1 swap.