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When reinstalling Windows 7, does the language, version, architecture (64-bit or 32-bit) or source (OEM, retail, or MSDN) matter?

I'm having trouble wading through Microsoft's marketing information. Does anyone know if Windows 7 x86 to Windows 7 x64 is a valid upgrade path? I know you can't actually use the built-in "upgrade" installation path; this is more of a licensing question.

Although that may have answered my own question: is this idea even possible? Or do "upgrade" versions of Windows function only when executed from inside the OS, and not when doing fresh installs?


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marked as duplicate by nhinkle Jun 28 '11 at 1:12

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Not as far as I can tell--my question has to do more with licensure than with the actual execution of upgrade installers. – bwerks May 24 '10 at 17:11
I'd agree with bwerks. This shouldn't be closed. – ChrisF May 24 '10 at 17:44
Did your friend buy the computer with Win 7 32bit pre installed? When I bought a copy of Win 7 it came with both 32 & 64bit versions on separate discs. One licence key for both. – pelms May 24 '10 at 21:21
up vote 2 down vote accepted

On the MSDN you get a single key which you can use with either the 32 bit or 64 bit version (but only one at a time), and I'm sure I've seen product descriptions where it states that you get both versions when you buy a disk. I can't find it right now to confirm that though.

You can't "upgrade" from the 32 bit to the 64 bit though as they are completely different architectures. So to move to 64 bit you have to do a complete fresh install.

I've found this link about Vista 32 bit vs 64 bit which confirms that they are completely different. It implies you get both on the installation disk (or two disks) but doesn't state it outright. Here's the same page for Windows 7

Ah - here we go - Amazon link:

Technical Details

  • Windows 7 Home Premium (includes 32-bit & 64-bit versions) makes it easy to create a home network and share all of your favorite photos, videos, and music--you can even watch, pause, rewind, and record TV

  • Single license, 1 installation

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Ooh, this is exactly what I'm looking for. I know someone who has a 32-bit version of W7, but has an x64 processor with 8gb RAM and wants to reinstall to 64-bit. His question to me was whether the upgrade would apply, or whether he'd have to buy a full install version of W7 64. I'd love to see that msdn link. – bwerks May 24 '10 at 16:31
@bwerks - unfortunately I don't have it any more as my subscription ran out. – ChrisF May 24 '10 at 16:33
Key doesnt matter, it works with x86 and x64 both – Shiki May 24 '10 at 16:36
I was considering doing this myself--I've got MSDN premium, and since the Windows 7 images are unkeyed I was debating just using one of my installers with his key. However, I'd really like it if I could find a more official "we allow you to do this" site where you register a key and they allow you to re-download applicable products a la Steam, Blizzard's or other such services. – bwerks May 24 '10 at 16:45
@bwerks - if you find one let me know ;) – ChrisF May 24 '10 at 17:15

No is the simple answer, 64 bit uses completely different programs so it would need to re-write your entire drive.
I suggest backing up all your files and doing a clean install

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