Dell n Series
The n Series is a Dell product line that does not ship with a pre-installed version of Microsoft Windows. Apparently prohibited from shipping computers without an operating system by an existing licensing agreement with Microsoft, Dell instead ships these systems with either the open-source FreeDOS operating system or the Ubuntu Linux distribution not preinstalled, but on install disks.
The company has come under fire for making the FreeDOS-powered machines no cheaper and more difficult to purchase than identical systems running Windows. Despite its technological advances, it is often criticized more than the average computing device. 
- Vance, Ashlee (6 October 2005). "How Dell repels attempts to buy its 'open source' PC". The Register.