The Ultimate Boot CD is free to download. The Ultimate Boot CD is a collection of as many diagnostic tools as possible consolidated into one bootable CD.
When you boot up from the CD, a text-based menu will be displayed, and you will be able to select the tool you want to run. The selected tool actually boots off a virtual floppy disk created in memory.
For a complete list of tools, their instructions and download, go to www.ultimatebootcd.com
Interested in a Windows version? Check out www.UBCD4Win.com
UBCD4Win is a bootable recovery CD that contains software used for repairing, restoring, or diagnosing almost any computer problem. It’s intended to be the most complete and easy to use free computer diagnostic tool.
List of tools and links to their instructions here
While free is good, Spotmau PowerSuite is OUTSTANDING. Highly recommended. Used it in countless situations. You won’t be sorry you cracked open your wallet.