From what I understand this is a known problem with ATI drivers and Windows 7- 64 bit OS. One problem is the cursor keeps changing sizes to about 4 times larger. If you reboot it fixes itself. But after more use it keeps changing. I also get a Black screen with freeze when trying to play a U tube video. ATI has a Hot fix out for the cursor thing but it doesn't help the Black Screen / Freezing.
Hot Fix Here: http://support.amd.com/us/kbarticles/Pages/ATICatalyst912Hotfix.aspx
Hot Fix Here: http://support.amd.com/us/kbarticles/Pages/ATICatalyst912Hotfix.aspx