I have manually copied the skyrim directory of steamapps from my old computer to a new one.
After installing Steam again, I tried to copy all files back again to start the game, but, when I start steam, it doesn't recognize Skyrim as installed, and need to download again 10Gb of game. :-/
I didn't know about the Steam Backup feature, so, someone can help me, I think it is a Windows Registry Keys that are missing, but I can't find anything on web related to that!
Any suggests?