OEM
Short for Original Equipment Manufacturer, OEM is a company that produces fully manufactured computers adding hardware, software, documentation and other components, making the computer a complete package. The company then sells the product under its own name and supports the computer to the best of its ability. Good examples of an OEM are Dell, Hewlett Packard, and Sony.
OEM is also a label often given to a software program or operating system that is included with new computer. Discs that are labeled as OEM should not be sold by themselves and if you're looking at buying a CD or DVD by itself and it's marked as OEM don't, it's likely a scam.