This maybe the AutoCAD funciton not install and license problem, suggest post your issue in the AutoCAD furom: http://discussion.autodesk.com/forums/category.jspa?categoryID=8, technical experts there will give your more help.
Also I would give you some suggestions:
1 check if you turn on the grip snap, you can use Shift+right mouse, select "Osnap Settings", then in the "Snap and Grip" tab, clear the "Snap On"
2 if you have installed Bitdefender virus scanner,please refer to the solution: http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=15127843&linkID=9240617&CMP=OTC-RSS....
Emily Xu, Autodesk Product Support
We appreciate your quick feedback on this forum