The camera turns on, but there is a green, yellow,

The memory is full. You need to erase some pictures or download them to your computer to clear space.

Link the camera to your computer using the data cable, open up the my computer bit on windows, (by opening up the green start button) find the camera (e.g. on my computer its removable drive E) then right click on it and choose 'format' it willwarn you you'll loose all the data but do it anyway, and the camera kind of re-boots its self, mine worked after this.