Arokia, are you really running Build 7000? If you are running anything below 7100 you had best switch out very soon. Starting July 1 of this year, the old betas are timing out. Download the free copy of the Windows 7 RC from Microsoft ( http://tinyurl.com/832nco
) and reinstall.
Beyond that, are you using the Windows 7 specific ATI Catalyst driver package, or are you using the Vista one? If you are using the Windows 7 specific one (WDDM1.1), try switching out to the Vista one (WDDM1.0). You lose a bit of resource usage efficiency with the Vista ones, but you might gain some stability.
Kurtis Whittington - Microsoft Windows Client Team