Save multiple copies of your work regularly. If the computer accidentally loses power, anything saved on the hard drive (including the Desktop and My Documents) will be lost.
You can save your files to the Desktop, but always save in another location such as a memory stick (USB device). Please note that documents downloaded from email and the web are opened in a temporary folder which is difficult to locate and lost once the program is closed, so you should immediately save that file to a USB device, or the Desktop using Save As. Remember to delete your files on the desktop once you are finished. If the computer is turned off or restarted, all your files will be deleted.
You can email documents to yourself as you work on them, but remember you must attach a file that has first been saved on a USB device or the hard drive, otherwise, it is a temporary file that will not be readable when you try to open it later. Another email option would be to copy and paste the text of your document into a second email for a backup copy. Make sure you are aware of the size of your file that you are emailing, as some email programs have a cap on the size of file that can be sent.
All the public computers are equipped with DVD read and CD read/write drives, so if you have a large file and a blank cd, you can burn your files to disk.