There are many different models of the TomTom sat navs that display a green light when charging and when your press the on button, it won't turn on, but charges fine. This problem is very common to occur on 'Go' models and replacing the battery pack will usually not resolve this problem. When this happens, the TomTom will charge, but will not power on, making it useless. I have a few TomToms, some are new and old models and they have suffered from the green light of death after a few years of good use out of them. I was trying to fix this problem without opening the sat nav and spotted a reset button, near the mini usb socket.
This reset button resets the software on the TomTom and also can be used as a quick repair solution for your TomTom sat nav, if it doesn't turn on, but charges fine. The reset procedure is very simple, all you need is a small pin or a pointy screwdriver, as a object to push the little reset button inwards. Then insert the object into the reset hole, on most TomTom sat navs it is located at the bottom, near the usb socket. Push in the object; this will push in the reset button.
Once you have pushed it in, hold it there for 10 seconds and then remove the object from the hole. The sat nav will be reset, now all you need to do is power it on, problem should be fixed! If still no luck i suggest you charge the battery pack again. If you have done the reset and still no luck getting it to turn on, then it is probably a electronic component on the circuit board that has shorted circuited. If that is the case, it is not really worth your repairing it, so buy a new sat nav!