I have bought a new memory card... Lexar 8GB, however when i put it in my phone and take out the original 4GB one there is a sign in the top left corner with a pic of the card with a '?' next to it. I'm not very good with technology either.... I have downloaded the software online and tried to sync it but nothing seems to work. What do i have to do so i can use my 8GB one? Thank you.