buy a new one
you have to take it to a professional or send it to Nintendo to get it replaced otherwise its impossible
It depends. If the touch screen works, but isn't clicking where you want it to, then you need to calibrate it. You can do this on the Settings. If the touchscreen is not responding at all, then...
Yes,of course it is a type of DS after all
you have to click on tools then click on Window Update.