Stopped working

[Shiki]

Hi,

I received my gamebuino yesterday and tried it.
I played asteroid and it was good, sounds worked as well.
I tried to restart gamebuino to change game. Off and On and it said something like "flashing loader.hex, please don't turn off".
It's when screen and sound stopped. I waited like 10 minutes, read the troubleshooting part of the "getting started" page and thought it was the battery (even if the power light was on).
I stopped the gamebuino, charged it and tried the micro sd on my computer and everything seems fine there.
After full charge, it's still the same render : no sound, no screen.

If the screen is blank when you turn on your Gamebuino

If you don't hear the start-up sound

You may be out of battery: turn your Gamebuino off, and plug it in (the "charging" led should turn on) for about one hour and try again.

You may not have a program loaded in your Gamebuino, so press C while you turn your Gamebuino on to flash LOADER.HEX from the micro SD card.

If a micro SD card is present, check that the C button is not jammed in the pressed position, or LOADER.HEX will be continuously re-flashed.

I tried those 3 points and nothing. Only the power light works

What should I do next ?

[rodot]

If it hanged while a program was charging, the program it contains now is corrupted. Could you try to upload on of the Gamebuino example throught USB using the Arduino IDE?

[Shiki]

I'm sorry, but... how can I do that? I'm a complete noob on all these stuff.
I only used Arduino IDE once for a simple purpose...

[rodot]

Everything is explained in the getting started page

[Shiki]

Alright, uploading via USB worked and I could play (tried setting, loader, hello).
Anyway, each time I try to go to LOADER.HEX (game title and pressing C), it goes "flashing loader.hex, please don't turn off" and then everything goes off
It's definitely not the battery, what am I doing wrong ?

Bonus question: should we remove the strap which is on the screen ?