I have recently bought 2 Megas and worked fine, but two days ago an error came out while uploading an sketch and then the Arduino disappeared from the ports.
I have a Late 2011 Mac Book Pro with Arduino 1.6.0 running well, I can still do projects with my ARDUINO UNO. My friends, who own windows 7 and windows 8.1 had the same Issue with both of the new Arduinos.
One of them make 1 board work when installing Arduino for the firs time in his computer, (Arduino 1.0.2 and Windows 7)
I was uploading this sketch on Saturday (I´ll attach it) and the first time it loaded, the second time it showed an error and the third time it just disappeared from my ports in tools. The same day the other Arduino had the same issue on my Mac and on my friends´ Windows 8.1 and Windows 7. It showed them the error that the device wasn´t installed. When we tried to update the driver nothing happened.
I´m not sure if we did it correct, but both boards haven´t worked yet.
My Arduino Uno works fine on my Mac so I don´t know what the problem is.
My other friend succesfully used another Arduino Mega, which is not new, on a computer that has never downloaded Arduino IDE, he used Arduino 1.0.2 and told us it worked fine
I read on the forum that Windows 8 and mac have most problems.
Cheap clone boards might not work or suddenly stop working. They have often very cheap crystals and bad capacitors.
The Arduino Mega 2560 got a new bootloader a while ago, a number of problems to upload a sketch are fixed.
Very cheap recent Arduino boards from Ebay have sometimes a CH340G chip, which needs a seperate driver.
This is what I do:
Connect it to Windows. Try to find the board in the Device Manager.
If the Device Manager doesn't see it, the board might be broken, or the usb-serial chip is bad.
If the Device Manager does see it, but not as a serial port, you need to install a driver.
If the Device Manager does see it as a serial port, but the Arduino IDE can not upload a sketch, perhaps the bootloader is corrupted and a new bootloader can be burned onto the ATmega2560 with a programmer.
It looks like the original. But it is an older version. If you buy the Mega in the Arduino Store, you get the 'R3' version. I think those are not 'R3', but that should be no problem.
If the picture of Italy on the back is sharp, and it came in an Arduino box, then it is an original one.
If you install the Arduino IDE 1.6.0 or unpack the zip-file of 1.6.0, there is a folder "drivers" in it, and in that folder are two executables for 32-bit and 64-bit Windows. Those install all the drivers.
If that doesn't help, then I don't know. It would very sad if you paid so much money and they are broken. Try to contact the seller.
Thank you for all your help, but they have told me that the Arduinos have a problem with the Bootloader. So, can you guide me, send me a tutorial or something with the proper procedure for burning a bootlegger to an Arduino Mega 2560
We have an Arduino Uno, I don´t know if that helps in certain way in the process
