Can the serial key of a retail version be checked by Run/regedit on Windows ?

[Petike]

Hello.

On my desktop, I'm moving to a newer version of Windows in a few days (from XP 32 bit to 7 64 bit).

Unfortunately, while my retail copy of ATTD is intact on its retail DVD (bought in 2011), I seem to have lost the retail packaging, and with it, my product key. And I honestly don't remember what the key was like. I'm kicking myself for not having written it down or copied it into a text file earlier. Frankly, though the retail box seems to be gone, I've tried already months ago to recover my key by writing to the distributor I bought the retail version from. Sadly, even after repeatedly mailing them and sending my purchase details, they haven't really replied to me. I'm still searching for the box and other external documentation where the key could be on. At this point, though, I'm not very hopeful.

However, I've thought of one other possible solution for the problem.

Could I try to open "Run" in the Start tab of Windows XP, then type in "regedit" and then try to search for my serial key manually ?
Could this work in any way ?
Or do the retail versions of Amnesia slip under the radar when it comes to Windows' memory archiving their product keys ?
If this could work, what installation path should I try to search for ? I'm guessing it would be Program Files/Amnesia/something, since that's how it's set up on my computer.

Also, searching this forum, I think I've read in another thread that product keys of retail versions tend to be stored in the saves and settings folder, i.e. My Documents/Amnesia/Main/etc.

Am I right about this or did I misunderstand something ?

If any of you can, please try to verify these two possibilities. I just want to be completely sure about exhausting all possible options concerning my lost product key, before I have to rebuy a whole new retail copy all over again. I'll gladly buy a new copy if there's just no other way of getting my product key back, but I'd prefer to have one last shot at finding it again before I have to switch to a new OS and kiss ATDD goodbye.

Thank you all for your help. I'll appreciate every bit of advice I can get.

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I've already asked about this problem back in June, see here:
http://www.frictionalgames.com/forum/thread-21691.html

In that older thread, Statyk advised me that the potential file I'm looking for should be labelled "installkey". But I was never able to find it until now, at least not in any version of the saves folder in My Documents, where it's supposed to be in retail versions.

I'm just completely baffled at this point.