My first Mac is a few Months old now, when I bought it , the Guy in the Apple shop set up the account for me, and ive been using it ever since with out too many problems . When I switch the iMac on it boots up and I can use it straight away, there's no asking for any password Etc, its just occurred to me what would happen if for some reason the iMac did not boot up , and I had to take it back to the Apple shop for repair, would this mean that the Apple shop staff would have access to my files and all my email account passwords stored on Firefox and Apple Mail .? What can I do to prevent any one possibly accessing my information should I have to leave my iMac with the Apple shop for repair..?