I have a PC that came with an OEM copy of Windows 7 Home Premium. I bought a Professional upgrade product key from Best Buy. I have since lost the upgrade key.

I know that I can use Magical Jelly Bean Keyfinder to get the key. The question is, which key is it finding: the Home or Pro key?


[I guess you have already upgraded your Windows]

When you upgrade a Windows OS, from what I know, the old key gets invalidated on MS server, and the new one is registered. The key is also changed in your registry. So, what you have should be the upgrade key.

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    The key installed in the original OS is never the same as the key on the sticker, this is true for all large OEM PC sellers like Dell, HP, Sony, etc, so that idea won't work. OEM's use Volume License Keys, the key on the sticker is a single user license key, and is different. – Moab May 10 '12 at 14:49
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    Its far easier to use 1 VLK to install millions of OS's than it is to install millions of different keys. – Moab May 10 '12 at 14:55
  • The old key doesn't get invalidated either. There are countless cases where after using a separate upgrade, an individual had to perform a factory recovery to the original installed OS, and use their original key. If using an upgrade key invalidated a volume license key (because it was there originally) that would affect millions of users. If using an upgrade key invalidated an OEM key from a sticker, it would make it impossible to perform a factory recovery and use that key again.... and neither of these cases happens. There are times when people have installed their OS more than once. – Bon Gart May 10 '12 at 16:28
  • From Windows 7 Professional EULA: "15. UPGRADES. To use upgrade software, you must first be licensed for the software that is eligible for the upgrade. Upon upgrade, this agreement takes the place of the agreement for the software you upgraded from. After you upgrade, you may no longer use the software you upgraded from." From what I've read, it seems this is the case for Windows Xp/Vista to 7 upgrade, nothing said about the Windows 7 to Windows 7 upgrade. – user127350 May 10 '12 at 20:29

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