I own a Samsung Galaxy Note 2 GT-N7100 and Wi-Fi does not work, he appears in the dim and when I open it, it closes itself automatically.. And I can not control my Wi-Fi button I do not know what to do Please, help

Only option I have is to reset the phone to default.

Should be under Settings -> Privacy - Reset to default.
This should work but you are going to loose everything on the phone.

Backup your phone with Samsung KIES: Bellow is the link
Kies | SUPPORT | SAMSUNG (http://www.samsung.com/africa_en/support/usefulsoftware/KIES/JSP)

Hope this helps
Grant