Here's some things you can do:
1. Try running V6 in Open GL Mode.
Go into your Graal folder and Send-to Desktop Graal6.exe to create a shortcut.
In the properties of the shortcut put -opengl at the end of the shortcut's target.
Optional: Drag the shortcut back into your Graal folder and pin the shortcut to your Task Bar.
2. Try Disabling Aero
3. Update your Video Drivers