If you want to play around with the Linux OS, and not have to install anything, look on the net for KNOPPIX.
See KNOPPIX
What is KNOPPIX? (copied for the website):
KNOPPIX is a bootable CD with a collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices and other peripherals. KNOPPIX can be used as a Linux demo, educational CD, rescue system, or adapted and used as a platform for commercial software product demos. It is not necessary to install anything on a hard disk. Due to on-the-fly decompression, the CD can have up to 2 GB of executable software installed on it.
I'm a not-entirely-new newbie and wonder about installing Linux. Would this be too ambitious a step?
I'm running Win 98 2nd ed on a Dell Dimension L566 CX - not the youngest of machines!
David

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic