I would start by booting your computer using a live-evaluation CD distribution. There are many of them. If you are able to burn CDs, download the .iso image files to your computer's hard drive and them burn them as CD images. Then boot your computer from the CD (you may have to make sure that your BIOS is set to allow to first attempt booting from the CD-ROM drive. Here are some examples of such linux distributions:
You can compare this list with the most popular distributions according to this site (the distributions with the most web page hits per day). The most popular distributions are often the user-friendly.
If you cannot burn CDs yourself, the distrowatch.com webpage shows how you can buy these CDs quite cheaply and have them mailed to you. Ubuntu will actually mail CDs free of charge so that you can your friends can try it out. Delivery may take some time, however.
The nice thing about using a live-evaluation CD distribution is that it allows you to test the software with your computer's hardware without having to install anything to your hard drive. If you like what you see and all of your hardware is supported, you can easily install the software to your hard drive. You can repartition your hard drive to share its space with both linux and Windows XP, so that you can continue to use both operating systems.
I hope this helps you.