If only 1 screen is flashing the problem is most likely the other screen, in your case the top screen. It could be something as simple as a ribbon cable that came loose. It could also be torn/worn due to the fact that it goes through the hinge. It could of course also be the screen itself. Hope this helps, good luck.

Hi,

I have the same problem as above but both screens flash white, is it worth my getting a new battery or is it terminal

If both screens are flashing white, you should try it out with the charger plugged in to see if the console switches on.

If you take the battery cover off (2 small phillips screws) lift out the battery and towards the back of the ds (nearest the trigger) is a little square sticker, it should be white with red dots on it, if it's turned red all together then it means you have water damage.

Hi Dan, Thanks for your quick reply. I took the cover off and checked the sticker its all fine so put the cover back on, tried charging again and after 1 hour charge its working..... one happy little boy and one relieved mum :) I guess the battery was just totally flat, I think i might pick up another battery just in case