In the DS menu press the Little ds at the bottom then click a sight like a cross the with your stylus press on the crosses and then it should tell you what is wrong then do the same with your stylus its probably to do with the screen rather than the stylus
Thanks for that Neilzulu1 I will keep a note of that. I tried that Kam_voo and nothing was happening, went on nintendo and they suggested what defenstrate said - and it worked!!!
Now shes happy on animal crossing once more, but still wants a ds lite for christmas. Thanks once again
M