There appears to be a multi-stage process that takes place when one starts working with Linux on a PC.
It goes somewhat like this:
Stage 1 - Attraction
You need a new operating system for an old PC that isn't supported by Microsoft any more, or you are sick of Windows 98/Me crashes, viruses, worms, spyware. However you aren't ready to jump into the pool without a lifejacket.
At this point you can try a Linux distribution with a "Live CD" that will install and run the O/S from a CD-ROM. You may have to set up the PC so it'll boot from an optical disk drive but that's it. If you like what you see - and if you see anything at all at this stage it's a good sign the distro will work with your video card - you can move on to Stage 2.
Stage 2 - Installation
Here you actually install the Linux operating system on your hard drive. Although it's possible to get Linux to dual boot with Windows, I've always found it easier to blow Windows away and just reformat the hard drive and install Linux as the only option. This means you likely want to have a second PC available to play with, or a second hard drive you can swap in and out.
Some Linux distros have a very easy graphical installer; others are text based and more of a challenge for a newbie. No matter what, you'll likely choose the default installation and then find out that isn't the best way to set things up. No matter - you'll be reinstalling again (trust me).
Stage 3 - Aggravation
Here is where you find out that your video card drivers aren't quite right, or your wireless card doesn't work, or your printer is really just a Windows zombie, or you want to use WPA encryption and its a PITA to set up. You'll do lots of research and Google-ing, plus you'll learn more than you ever wanted to know about the Command Line and Linux file systems. Don't give up though.
Stage 4 - Experimentation
Here you'll discover that there are another 100-odd Linux distros out there and you can download them and install them if you want. You may actually find another one that's faster on old hardware, that looks cooler, or that's easier to configure. At one point you'll install and configure your Linux trial machine with about 3 different distros and I guarantee you'll cock up your original installation in the process. Now is a good chance to reinstall the right way with a separate partition for data at least.
Stage 5 - Maturation
You'll settle on the one Linux distribution that works best for you and just install that on your PC. You'll keep it up to date and learn to use it in preference to all the other ones. You might even get a text that deals specifically with your favorite distro. In my case it's Ubuntu, although I also use Vector Linux on a really old laptop I have. At this point you'll have arrived as a Linux user.