The only file to copy (I don't know where it is on Windows though) is wallet.dat
This is
not true if you don't want to "have to reload again all blocks from the internet". To avoid reloading all the blocks, you also have to copy the entire blockchain.
Indeed
You can copy the wallet.dat back and forth, but NEVER attempt to use it on two different computers AT THE SAME TIME, or you risk losing bitcoins forever.
Lol stop the FUD
FUD? You are aware that Bitcoin-Qt is not designed for this and that there is a significant risk of permanent loss of bitcoins if you do so, right?
Permanent loss requires you to lose the private key associated. Please tell me how is it possible to lose the key when you have 2 copies of the wallet containing it?