I mentioned this in another thread a while back but thought this could be useful for some. The Ultimate Boot CD is a free CD you can download and burn. It contains self booting DOS and Linux utilities for a large number of purposes. It is also possible to add your own DOS programs to the disc and then run them from the CD, so it is also a self booting DOS CD.

On the CD is included a lot of utilities including:

CPU Tests, stress and burn-in.
Memory Tests.
Peripheral Tools (ID drives and ports).
CPU identification.
System Information (very handy if repairing a PC you don't know).
Benchmark Tools.
BIOS Tools.
Hard Disk Installation Tools (MaxBlast, DiscWizard, Disk Manager etc...)
HD Diagnostic Tools (all manufacterers own tools - Drive Fitness Seatools, HUTIL etc).
HD Device Management Tools.
HD Wiping Tools (good for completely erasing data).
HD Cloning Tools.
HD Low-Level Editing Tools.
Partition Tools.
Boot Managers.
File Tools.
NTFS Tools.
Anti Virus/Malware Tools.
Network Tools.
DOS Boot Disks.
Linux Boot Disks.

So as you can see there are a lot of useful utilities on this CD, allowing you to do many tasks by just booting this CD. Great when you can't get your OS to boot or are trying to repair a broken system.

You can get full details and download the ISO from http://www.ultimatebootcd.com/