Which version (32 vs 64 bit) to install?

[Lcarvone]

A buddy of mine had a hard drive go bad on a Dell Inspiron laptop. The product key is on the laptop (Windows 7 Home Premium) but I cannot tell if it is the 32 or 64 bit version. He has no recovery/reinstall media but I have one of similar vintage that should work with his key. Checking the service tag on Dell Support gives no help (both 32 and 64 bit version drivers are available and no details in the original system configuration that I can tell...). It only has 3 gigs of ram installed so either version should read all the memory.

So my question is, are product keys tied to the OS per category (e.g. Windows 7 Home Premium) or even more specifically to the category and type (e.g. Windows 7 Home Premium 64 bit)

 

[RebateMonger]

Win7 Keys are good for either x32 or x64 versions. However, if using Dell Install media, you shouldn't need to enter a Key during the install process.