Win7 is a BETA. Dotn expect things to work in there like they do for Vista or XP. It is not ready to be used as a full time OS and it is not a secret that ATi has some major problems
with Driver support for Win7.
So your best option will be to use the Drivers that either come from Windows Update or the latest set of drivers. Which ever are newer. As for the OpenGL, there is a program out there on the net that you can download that will unlock OpenGL in Win7. It could even be linked to in our Win7 FAQ Thread
in the Windows area.