Hello.
I have a littel problem. I hide all my free games and now i want bring back one of them.
Someone can tell me how to do that?

In the Library page of your Account there should be "show my hidden games" towards the end of the page, just under the visible games.

Select the game and, on the right side, click on the last option: "unhide game".

Hmm... so i have little problem, cos i don't have anythink like that. ;p
Any idea?

Try hidding one more game and then unhide it.

I don't have more games. ;p
I take free Wither and want to hide all free game, but when i hide the last one, Wither dessaper with others.
Now i try to bring back my reward.

You should have a show hidden games button on the bottom right of your shelf. If you don't, use another browser.

That'll be the way to do it.

Edit: Here's a pic to help.

I'm not 100% sure, but I think I've heard that there's a bug in a shelf view, causing all games to disappear when you hide every single free game.

Try refreshing your account - https://secure.gog.com/account/refresh