PLEASE PLEASE HELP, i have a message comming up on my sat nave screen incorrect disc please insert correct disc i bought an update off a guy and i think its buggered my system... i dont want the damn update now i just want my sat nav to work again, i removed the disc and replaced with the original but i'm still getting that message, i have tried battery disconnect for 30 mins with no avail please help guys i'm gutted the seller of the killer disc is saying its a dirty lens on the laser however im some what skeptical .....