Get Windows 7 for Free

MSDN Academic Alliance

Expires: No expiration date

Who’s eligible: College/university students in technical departments (international)

If you are enrolled in a science, technology, engineering, or math department at an educational institution that belongs to the MSDN Academic Alliance, you can get free software for use in your studies. (There are also similar offers for students in visual, illustration, design, and art departments.) The program also extends to members of IEEE and ACM.

Apart from Windows 7 you can also get 32 bit and 64 bit version of other OS (like Windows XP and Windows Vista)for free. You can also get software like Office Project and Office Visio( ad many more for free)