The process of upgrading one's operating system can differ widely based on what operating systems you are moving to and from. However, most operating systems currently available have automated setup programs that can be run from your current operating system, and often even have special versions of the operating system specifically for upgrade purposes.

This does not hold true as a rule for migrating between different families of operating system, but many helpful guidlines and how-tos can be found on the internet, or published in book or video form.

The most important thing to keep in mind is that before you do anything, you should back up all your files. Anything that's difficult or impossible to replace, you should have stored someplace safe, such as CD, Zip-Disk, or another hard drive. We cannot stress the importance of this enough. The only safe place for sensitive data during a change of operating system is not connected to the computer. After that, follow the directions, and, if possible, get advice from someone who has done it before, preferably with the operating systems that you are working with.