Try Linux without installing it
It is possible to run Linux without actually installing it on your computer. This is done using a "Live CD" and is the perfect way to see if you like Linux or if it will run on your computer. Linux runs directly from the CD and nothing is installed on your computer so it is completely safe. The two most popular Live CD Linux distributions are Knoppix and PCLinuxOS.
The first step is to download or obtain the ISO (also known as "image") file for the Live CD. Knoppix can be downloaded from http://www.knopper.net/knoppix-mirrors/index-en.html and PCLinuxOS can be downloaded from http://www.pclinuxonline.com/pclos/html/download.html. *See get linux for more information on downloading ISO files with a high speed (broadband) internet connection or obtaining a copy of one if you have a slow (dial-up) internet connection.
Next, you will need to burn the ISO file on to a CD. The help files for your CD writing software should give you directions for creating a CD from an ISO file as it is slightly different from creating a regular CD, or you can read some frequently asked questions on ISO's at LinuxISO.
The last step is to place the CD in the drive and restart your computer. After a couple of minutes (a Live CD is slower than an installed version of Linux as it has to load everything every time it starts up) you will get the login in screen for PCLinuxOS (Knoppix does not require a password). The password is the same as the username. *If your computer doesn't start from the CD then you can change this setting by pressing ESC, DEL or F2 (depending on your computer) when your computer is starting up and choosing the option to boot from CD first.
You now have a fully working version of Linux to try out. Everything works in the same way as it would if it were installed on your hard drive. Have fun!
When you are finished shut down your computer and remove the ejected CD. When you start your computer the next time without the CD in the drive you will be back to your old operating system.
Knoppix has more information on Linux Live CD's for new users or for a complete list of Live Cds go to Frozentech.