Windows product key recovery across partition

I have a problem which I would appreciate some advice about:

Recently I accidentally deleted a system file in my Windows Vista Ultimate (don't ask), and I didn't have the installation disc. I borrowed a copy of Windows 7, and installed it on a separate partition of my hard drive. I then downloaded a Windows recovery disc and fixed my Vista, but now it's asking me for my product key, which I don't have.

I have downloaded a couple of different free keyfinder programs (magic jelly bean or something, and another one), but while running Windows 7 in my separate partition, I can't detect the product key for Windows Vista in the main partition.

So, can anyone tell me how to detect the windows product key across the partition?

Thanks in advance for any replies.

 

What happened to your COA sticker?

 

Have never tried it but it sounds like it may give you access http://majorgeeks.com/ProduKey_d4953.html

Please let us know if it works in your situation.