Another way you can try these out without needing a new computer, assuming your PC has a reasonable amount of ram, 2GB+ is use a program like VMWare Player, Virtual Box or even Microsoft Virtual PC 2007, all free, and probably would recommend in the order of suggestion, and it will let you install the trial operating system without it affecting your Windows (or OSX) install. When you are finished just deleted the virtual machine and virtual harddrive and it will free up the space that it was using. Its what I do when I want to go through a lab for my students before I give it to them or if I want to just expolore new things..