Ferooxidan: Per Microsoft contract and public "FAQ solutions", when Windows (until Windows 8) is sold with a OEM PC (i.e. Dell, Gateway, etc.) it is LOCKED for only that make model PC (based on the CPU, BIOS, even a CASE identification tag) that will prevent Windows from booting or being installed when 'issued' from a OEM.
A OEM BUILDERs edition is NOT the same thing, these are sold that like the normal "off the shelf" at XYZ store Windows Edition, are usable per license on any computer (only limited to usually 1 copy PER computer at a time). These must be activated with Microsoft and after THREE such activation requires the builder/end user to CALL MS Support to reactivate that valid license any further (you had 2 hard drives fail and this was the 4th time to load the OS, you have to call MS to get it to work).
It had been this way from XP through to 7, only changing in 8 now with the licensing restrictions being like a OEM Builder's edition, whether the source of Windows came from a OEM company (Dell, etc) or not.