2 devices, not one that works

the first unit has been running five days ... after the button is stuck, unable to navigate the menu.
As the product seemed suitable to our use, we asked for an exchange (received quickly, no complaints on that side!) And, another problem, the machine ejects itself from the connection, and the pilot did not recognize. impossible to recognize the gogear by the computer, even after reinstalling the driver.
second return, and passes something else ...