(pronounced as separate letters) Short for original equipment manufacturer, which is a misleading term for a company that has a special relationship with computer producers. OEMs are manufacturers who resell another company's product under their own name and branding. While an OEM is similar to a VAR (value-added reseller), it refers specifically to the act of a company rebranding a product to its own name and offering its own warranty, support and licensing of the product. The term is really a misnomer because OEMs are not the original manufacturers; they are the customizers. Thanks Wikipedia
Meaning that you wil get the product only... no extras. If you buy a hard drive new, you would get some kind of install disk and a cable... with OEM you will not get the "extras"
and windows is an operating system sold by itelf... unless you buy a complete system, you will not get the OS already on a hard drive. As was said above by my fellow TF member..