I need to reinstall Windows on a laptop. I have the product key (its on the laptop), and I know it is Windows 7 Home Premium.

I need a way to determine if 64-bit or 32-bit Windows is installed, so that I can download the correct one from Microsoft. The computer is messed up so I do not have access to Windows to check it with systeminfo.

I took out the hard drive and hooked it to another computer, but when I run systeminfo it just gives information for the host computer, I did not see a way to change this.

  • 3
    You do understand the product key for Windows 7 Home Premium can be be used to install 32-bit or 64-bit installation. If the HDD is attached to another computer then you can view the contents of the HDD and determine what you had installed per Fran's answer. – Ramhound Jul 2 '12 at 15:24

If you see a folder in the root of that drive named Program Files (x86) then it has 64-bit Windows installed.


A slightly more accurate way of detecting 64-bit windows is to look for folder %SystemRoot%\SysWOW64 (commonly Windows\SysWOW64) since it contains the binaries windows uses to launch 32-bit applications it should not be present on 32-bit windows installations. This is a little more accurate than checking for Program Files (x86) because I recall seeing an installation option somewhere in Windows Vista which allows that folder to be renamed, but I've never seen one for SysWOW64.

  • 1
    -1: It's not officially possible to relocate Program Files or Program Files (x86) via an unattended setup anymore. It was possible with XP. Obligatory Old New Thing Reference – afrazier Jul 2 '12 at 21:01
  • 2
    "not officially possible" does that mean "unofficially it's still possible"? – Bob Davies Jul 2 '12 at 21:03
  • 1
    It's not possible with the WAIK. I wouldn't be surprised if someone's come up with a nasty hack that appears to work though. N.B.: I'm not talking about people simply junctioning the folder to another drive, which is also unsupported, but actually renaming Program Files. – afrazier Jul 2 '12 at 21:07
  • 1
    Good to know thanks. Though I think I'll stick with my option since in my experience it's slightly less fallible than the alternatives. – Bob Davies Jul 2 '12 at 21:09
  • 1
    Why exactly was this voted up so many times? The user was running Windows 7 Home Premium. There is NO WAY he doesn't have Program Files (x86) if a 64-bit version was installed. – Ramhound Jul 5 '12 at 15:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.