Crashes and freezes are inevitable. Be sure to back up your files.
This, of course, good advice. If the data you need to back up is critical to your job, let us design a secure and easy backup system for you!
For less critical data, make frequent backups to an external device (flash drive, external hard drive, cd or dvd). This way, you can deal with a system crash without also having to deal with the grief of possibly having lost all your data. It really does make life more bearable.