Linux distros for older hardware
Microsoft lately has been challenging Linux's suitability for older hardware, so it seems like a good time to look at Linux distributions that can run on older machines. I took six distributions for a test run on an old machine, and also tried software that turns old hardware into a thin client. The bottom line: Linux is still quite suitable for older hardware. It might not turn your aging PC into a powerhouse, but it will extend its lifespan considerably.
For these tests, I dug out Igor, an old PC that had been collecting dust in my closet. Igor is a Pentium II 233MHz machine with 64MB of RAM, an 8x CD-ROM drive, a 3GB hard drive, and an integrated ATI 3D Rage Pro video card with 4MB of video RAM. You can run Linux on older and slower machines, but this is the most under-powered machine I had available.
Next, I selected a handful of lightweight Linux distributions that looked promising, and started downloading. The distributions ranged from popular "mainstream" distros such as Slackware and Debian to distros that are specifically developed for lightweight machines, such as Damn Small Linux (DSL). I apologize in advance if your favorite lightweight distro is not represented here.