Memory Stick Says It Needs Formatting

"I have a memory stick which contains lots of data, but it says needs to be formatted when I tried to access data on it. Inserting the memory stick to my computer, Windows system recognizes it as a RAW disk and asks me to format it before I can use it. CHKDSK says it is not available for RAW drives on memory card. I have searched online, and many people that the memory stick is corrupted. I need to use a data recovery program to get back files on an unformatted memory stick. So I hope somebody can recommend a useful data recovery tool with which I can recover files off the unformatted memory stick and fix the notformatted error."

Memory Stick Needs Formatting Message

"I have a 2GB memory stick for my Sony digital camera, but the problem is that I cannot access the memory stick. When I inserted it to my PC, it says disk in drive is not formatted do you want to format it now? I also receive CHKDSK RAW error on memory stick. Reinserting it to my digital camera, it also said that memory stick needs to be formatted before I can use it. I cannot format the memory stick because it contains lots of important data without any backup. Please tell me how to recover data when a memory stick asks to be formatted in both digital camera and computer? How to fix the not formatted error without formatting?"