Please install the latest Inventor Fusion 2013 and see if the issue is still there
And could you give some information about your gaphic card?
Have you tried Inventor Fusion 2013 yet? And if that doesn't help, please delete the Fusion user configuration files with below steps:
1. Input "%appdata%" in Run
2. Goto "Autodesk"
3. Delete Inventor Fusion related folders
Hoping that works!