dont laugh because this an easy solution maybe......
but if one of your friend have nokia 3650 then you can put your memory card inside and then there is an option /format memory card /and return it to your device
Step 1: make sure the meroy card is in the phone
Step 2: open FILE MANAGER
Step 3: press the menu button and select the MEMORY CARD Menu
Step 4: Select "Format memory card..."
DONE! how easy was that! this will take a while, i use a 32meg card and it takes a good 5 minutes so just close the screen and let it do its job!