Using win7 32-bit license key to activate a win7 64-bit installation

This would only be possible if they are same edition and your current license is a retail license.

You can use a Windows 7 Home Premium key with a Windows Professional for example. So you must at first establish that they are same edition and your license did not come preloaded on which ever system you are transferring it from.

Just bought a 2nd hand laptop which apparently had win7 32-bit originally, I believe the first owner is not using this win7 software any more.
Can I use the same license key to install and activate a win7 64-bit instead. ??

I intend on using the only one instance of win7 64-bit ?

 Thx for the help.

If the laptop in question has a product key sticker for 32-bit Windows 7 - you are stuck with the 32-bit architecture version *because* it is an OEM licensed product *unless* you purchase a 64-bit OEM license for WIndows 7 and use it on this system (and replace the sticker) OR you purchase a retail version of Windows 7 - where you can use wither 32-bit or 64-bit.

The sticker looks like this:

So - again - the limitation comes because of the OEM status. If it had been retail licensed, you could have clean installed in either direction as ooften as you like (32-bit to 64-bit and vice-versa.)

Previous post about the same thing:
http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/windows-7-pro-oem-32-bit-64-bit/279a9ccb-a1dd-493c-ad27-6496353f7395