Note: Does not work on Windows 8

For 32bit and 64bit.

AutoCAD software lets you design, visualize, and document your ideas
clearly and efficiently. From powerful 3D modeling through robust
documentation and visualization tools, AutoCAD software provides the
power and flexibility to work more productively from concept through
completion. If you haven.t looked at it in a while, now is the time
to check out AutoCAD 2010.

http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=2704278