The girl at your school was only half right. AutoCad IS for Mac & PC, BUT there are different versions. It sounds like you have the Windows version on the USB.
The girl at your school was only half right. AutoCad IS for Mac & PC, BUT there are different versions. It sounds like you have the Windows. Find Serial Numbers & Product Keys. For a 2013 or earlier product, your serial number and product key will be printed on the label of the product packaging.
Since you mentioned school, I'm going to assume it's an educational version? If so, you can download any Autodesk Software for free if you're a student/faculty member. http://students.autodesk.com/
Sign up/in, and 'purchase' & download AutoCad for Mac (2013). Use this .dmg file to install AutoCad for Mac!
1 more thing: There's a bug with the serial numbers in the Mac version. You have to install it first as a trial, and then once you open it for the first time, then register it with your serial number. (There should be an article on the Autodesk site about this)