Lance Painell, Microsoft:
“Fundamentally, if a consumer is building their own PC, and we know a lot of enthusiasts do, then the OEM product is obviously a good product to do that,” Painell assured me.
“If they build their own PCs and they understand the complexities of setting up a PC from bare tin then by all means they’re welcome to take the OEM product and install it on a PC. It is designed to be installed on a new-built PC.”
Level of support
If you buy a boxed copy of Windows 7, you’ll get 90 days of free support, via email and telephone, from the moment you activate it. You're also entitled to installation support, while chat support - we're told - will be available "in the future".
And what do you get if you buy the OEM version? “The simple answer to that question is none,” explains Microsoft’s Painell, “because what typically happens with OEM products is that the [PC maker] supports the installation of that product and the end-user. That’s one of the core differences between OEM and FPP [Fully Packaged Products].”
Instead, you must fall back on the Microsoft Knowledge Base, forums and friends.