Microsoft should continue to offer security patches for WinXP for another few months.

Microsoft has NEVER provided technical support for "OEM" versions of anything. The "OEM" means "Original Equipment Manufacturer," and terms of sale when the computer maker buys the license require that the machine manufacturer who sells it must provide all technical support and is the only one who can ever have been expected to "support" an OEM copy.

The OEM contract, between Microsoft and the machine maker, actually prohibits resale of the license except with a machine on which that copy is preinstalled. Since "recovery copies" are sometimes necessary, and since some builders were overly optimistic about how many machines they'd sell and have lots of "extra licenses," aftermarket OEM copies are common, and most of them probably can be "validated;" but there's always the suspicion that an OEM copy may have been installed on another machine and you may have difficulty convincing them that your specific copy is only on your one-and-only machine.

John