Unable to start Windows to determine whether the version of Windows 7 Home Premium is 32 or 64 bit. The product key is available. That is all I have.

Looking to acquire re-installation media but need to know the correct version. This requires choosing which version was originally installed, 32 or 64 bit.

Is there a way to determine if 32 or 64 bit was originally installed from the product key?

Internet search has only shown how to find the key (which I already have). This is not a duplicate of; Is there a way to establish what version a Windows 7 product key is? which installs software to check. Can't do that in my case.

  • A Windows 7 Product Key could be used for either platform. Of course on the retail space You would either purchase a x86 or x64 installation disk.
    – Ramhound
    Dec 7, 2012 at 16:32
  • This is OEM on a Dell. Can't seem to find what it originally came with 4 years ago. The build sheet doesn't have those details.
    – CharlieRB
    Dec 7, 2012 at 18:18
  • Doesn't matter.
    – Ramhound
    Dec 7, 2012 at 18:29
  • You're right, it probably shouldn't matter, but when trying to download re-installation media and you have to choose either 32 or 64 bit it matters. Maybe I need to reword my question about wanting to know what was originally installed.
    – CharlieRB
    Dec 7, 2012 at 18:36
  • There is no way for us to help you figured that out if you don't already know unless its original installation. The key cannot be used twice on two difference computers thats obvious.
    – Ramhound
    Dec 7, 2012 at 20:55

2 Answers 2


I don't think it can - when I got W7 it came with both 32bit and 64bit discs, but only 1 code;

More research shows

"Yes, it is valid for either 32 or 64 bit, its up to you which architecture you want to use. Please note 1 key, 1 license. You can't install 32 bit one computer and install 64 bit on another computer using the same key."



You can't find out which version was installed by the key.

Since Vista, you have one key and two setup disks: for 32 bit and 64 bit versions. (Boxed versions of Windows 8 Upgrade also have two disks.)

So to tell which version was installed you have to either boot to that system or at least look at its file system. There's Program Files (x86) folder in the root of 64 bit installation, and SysWOW64 folder in Windows folder.

Then you don't need to know as it doesn't really matter.

  • If there's more than 4 GB of RAM install, you definitely need 64 bit version.
  • If there's more than 2 GB, you can use either version.
    (32 bit takes less disk space, less memory in some cases.)
  • If there's less than 2 GB, you need 32 bit because 64 bit requires 2 GB of RAM to run.

You can also check whether the installed processor is 64 bit capable or not. Most probably the processor can run in 64 bit mode unless it's really old.

If you don't know the amount of RAM or processor, you can look this info up in the Internet using the model number of your laptop.

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