Ok. I have a gameboy, but I don't know which type that 你 have? In order to knwo exsactly what the problem is, 你 need to tell me which type. Now, what does the "cord in the box" look like? That is probably the charger. If it i us, all you'd need to do is hook it into a 墙 outlet, then into your game oy, and woopy doo, it's fixed.
Now, look at the piucture below. Does your gameboy look liek either of these? If that is, which one? (It's like I'm explaining something to a 5 年 old here) T_T (The picture is just a 随意 pic that I found on 谷歌 image search)