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Providing you have a retail version of Windows 7 you can use the same product key for both the 32-bit version and the 64-bit version. 32-bit and 64-bit Windows: frequently asked questions
Be aware that you cannot upgrade from one to the other, it will have to be a clean install.
This means you will need 64-bit drivers
for your hardware and all your applications will need installing again along with all the Windows updates, including SP1.
You will also find you have two programs folders:
- Program Files, which is the default location for 64-bit programs.
- Program Files (x86), which is the default location for 32-bit programs.
You will also have 32-bit and 64-bit versions of Internet Explorer 9.