Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Test-Drive From a CD
In times past, the only way to see if Linux would work on a given PC was to install the OS. Times change. These days there are many so-called Live CD versions of Linux that boot and run from a CD-ROM.
Now, here comes the question that's arrived in my inbox so many times, I'm embarrassed for not having spelled out the answer before.
Question: "How do I download a stinkin' CD?"
Answer: Linux Live CDs and installation CDs are often made available for download as files with an .iso extension. These files are a snapshot image of a CD-ROM's file system. You grab the ISO file, feed it to your CD-burning software of choice, and a few minutes later you've got a shiny disc that will actually do something cool.
Set Up a Dual-Boot System
If you like what you see, or you wanna see the real deal, why not set up your machine to dual boot? At power-up, you'll get to choose between Windows or Linux. On the Linux side, you'll have the increased performance of a true installation (as opposed to running from a CD), the ability to install additional software, a home directory to call your own, and so forth.
Partioning the Drive
Most Linux installers default to using two partitions: one for the operating system and all user data, and one for the swap partition. (A swap partition is akin to Windows' swap file; Linux just happens to use a separate partition for virtual memory.) But there's a better way: Create one partition for the operating system, one for user data, and one for swap space. This way, if you ever need to reinstall Linux, you don't lose all your files and settings: You can tell the installer to format the OS partition, but leave others alone. In this fashion, you're far more protected from unintentional system hosings if you're the type to get under the hood and tinker around with your new OS. Your worst-case scenario is a reinstall that won't kill off your data.