Hi fellow warriors,
Here's my problem:

I installed a cracked version of the game to try it, and then bought the serial key on GOG.com.

Fact is that there is no entry in the registry so I can't apply patches because : Game installation not found, please reinstall.

I need someone who has windows 10 64x to copy his reg key and then send it to me.)

Please help me!
Peace

Um, uninstall stolen version of game and install purchased version = problem solved.

GOG said they would refund games if not satisfied. The dark side (if you read the notice) is that they only refund if there is a problem with the installation and/or the game is not working properly.
Not taking chances I tried the game before.
You're dumb to call me a thief.

PS: Don't want to lose my saved games.

You OWN a purchased GoG version now... right? So just use that,.

You can easily transfer savegames by find thing the save files and moving them around in windows explorer.
no need to fiddle with keys or whatever

Thanks it worked. Just copy and paste the file :/