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Windows 7 and Vista Activation FAQ: how do language, version, 64-bit or 32-bit, and source affect ability to install and transfer Windows licenses?

It is possible to change windows 64bit to 32 bit without re-install windows? I install windows 7 64 bit on my PC last night and I didn't know that it was 64 bit but when I install some software it say your windows is 64 bit can't install. so I got problems, I don't want to format the windows or re-install the windows because it will take at-least 30 mins or more.

Is there any software or settings can change 64bit windows to 32bit in 5 mins or less?

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marked as duplicate by Sathya Aug 26 '11 at 16:59

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.

Related: Windows 7 and Vista Activation FAQ: how do language, version, 64-bit or 32-bit, and source affect ability to install and transfer Windows licenses? (not an exact duplicate, but the answer can be found directly in the answer). – Breakthrough Aug 26 '11 at 16:15
up vote 7 down vote accepted

No, there is no way to do this. The 32 and 64 bit versions are signifcantly different on a kernel level, and there is no way to change this without a re-install of the OS.

Windows' WoW64 subsystem can happily translate addresses and function calls from the 32-bit world to a 64-bit environment, so most 32-bit applications (with a few exceptions) should have installed in the first place.

For more details, see this article.

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On 64-bit Windows, 32-bit programs run in an emulation layer. This emulation layer simulates the x86 architecture, virtualizing the CPU, the file system, the registry, the environment variables, the system information functions, all that stuff. If a 32-bit program tries to look at the system, it will see a 32-bit system. For example, if the program calls the GetSystemInfo function to see what processor is running, it will be told that it's running on a 32-bit processor, with a 32-bit address space, in a world with a 32-bit sky and 32-bit birds in the 32-bit trees.

And that's the point of the emulation: To keep the 32-bit program happy by simulating a 32-bit execution environment.

Commenter Koro is writing an installer in the form of a 32-bit program that detects that it's running on a 64-bit system and wants to copy files (and presumably set registry entries and do other installery things) into the 64-bit directories, but the emulation layer redirects the operations into the 32-bit locations. The question is "What is the way of finding the x64 Program Files directory from a 32-bit application?"

EDIT: THIS IS taken directly from Wikipedia

32-bit applications that include only 32-bit kernel-mode device drivers, or that plug into the process space of components that are implemented purely as 64-bit processes (e.g. Windows Explorer) cannot be executed on a 64-bit platform. Service applications are supported. The SysWOW64 folder located in the Windows folder on the OS drive contains several applications to support 32-bit applications (e.g. cmd.exe, useful to register 32bit windows services, odbcad32.exe, to register ODBC connections for 32-bit applications).

In summary, the clear answer to this question is NO.

(Usually software comes in versions for 32 and 64 bit machines.)

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False. Many 32-bit processors come with 64 bit emulation, and 64 bit processors can certainly handle 32-bit. – soandos Aug 26 '11 at 15:43
If you can emulate 64 with a 32, shouldn't you be able to do the reverse? (emultate 32 with a 64)? – wizlog Aug 26 '11 at 15:44
Can't what be reversed? – soandos Aug 26 '11 at 15:46
This is completely wrong, the x86-64 instruction set contains the entire 32-bit instruction set (implemented in hardware.) Any 64-bit CPU of the x86 architecture should fully support 32-bit software. – robjb Aug 26 '11 at 15:47
It's no longer wrong information after the edit, but still doesn't clearly answer the question. – robjb Aug 26 '11 at 15:53

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