Sandisk Cruzer 16GB has just stopped working

My memory stick was working fine, and all of a sudden it is telling me that it is either passworded or not found, I really do not want to format it again as I need to get at the documents that are on it. Please can anyone advise me what to do - is there anyway I can get the information off and even transfer elsewhere? Also, why did this happen as I always ensure that I ensure that it is safe to remove the stick from the computer before doing so.
 
Back