Which version of IE9 are you using ? If you are using the 64 bit version of Windows 7 then you must use the 32 bit version of IE9 as the other is not stable. You could head over to Tools and Internet Options click on the advanced tab and see if the Graphics acceleration is ticked for software and not hardware if you dont have a graphics ard installed and are using the on bpard one. A complete removal and reinstall has been a good fix for this problem in the past.