A "boot disk" is a floppy disk that contains essential files to restart or "boot" your PC in the event of a problem that prevents you from booting the normal way. In short, it can be a lifesaver.

But many people never bother with making a boot disk, or at best, accept the generic, limited boot disk that Windows offer to create during installation. That can be OK provided you use your system as a "black box" and never change it much. If you don't add or remove much hardware or software, if you don't alter the factory configuration, and you don't succumb to the temptation of "Gee, I wonder what this setting does...", your PC may never suffer a bad crash.

Think of your microwave, stereo, or other complex home electronics gadgets. Part of the reason they run so reliably is that you can't change much, if anything, about them -- you just use the device in the ways the designers intended, period.

But PCs are very different. If you're like me, over the life of your PC you'll substantially alter your hardware configuration and perhaps change the OS itself. You'll try all kinds of new software. And hardly a day will go by that you won't try some new trick, tweak, or twiddle to make your PC run as well as possible. Heck, I have some old PCs here where about the only thing that hasn't been changed is the steel case itself.

If you're at all like this, you need a good, well-equipped boot disk so you can control your PC from the lowest levels and ensure that you can get the results you want, or at least get back to a safe, stable minimum setup.

Even if you're not as hard on your gear as I am, you still can have plain bad luck -- a disk crash or other failure -- that leaves your PC in deep kimchee. For that, you also need a good boot disk, and maybe one that goes beyond the bare-bones basics.