my touchscreen has been acting weirdly lately. sometimes when i play pokemon diamond and whenc i battle the touchscreen picks moves and navigates through the screens during battle. also whenever i mine underground my touchscreen will look for gems by it self and when im in the mining screen it uses the pickaxe by its self. if i had to describe it i would say that a ghost was doing it lol
Well it cetainly isn't a virus, more likly to be a hardware fault of some kind, if you have a screen protector, remove it and see if the problem is gone. my brother once had his touch screen stop working completely, turned out the screen protector was pressing down the bottom right corner therefore not registering any other presses. If that dosn't fix it try re-calibrating the screen.
usually if touched screen act weird recalibrate it is the best choice to do. Once my original DS the touched screen completely not working. turn it one, go to calibrate, and it work as good as new XD