They you got to playing with it. You installed all sorts of applications, some commercial, some shareware, some free-ware. You cleaned off the stuff that comes on a Mac hard drive that you thought you'd never need again. I mean, who would ever need QuickBooks for your personal computer?

The about six weeks later, you decide that now is the time to start that mail-order orchid business you always dreamed of. Now you would like to at least try out QuickBooks, but you've already thrown it away and emptied the trash.

What do you do now?

You just reinstall.

"But Don, when I start up my machine from the CD or DVD that came with it, it wants to reinstall the whole system and the applications that came with it."

Ah, but there is another way. On most recent Macs, the original CDs or DVD that came with the computer has a package that will allow you to reinstall all the apps without touching the operating system. And if you only want a specific program reinstalled, you can customize the installation.

Here's how: We'll use a 12-inch Powerbook (about a year old) for an example. You don't have to restart the computer from the disc to do this. In this case, put the PowerBook G4 Mac OS X Install Disc 1 into the computer. You should see several icons on the screen, like the Read Me and other items. The one you care about here is the one that looks like a cardboard box with sticks of butter in it labeled "Install Bundled Software Only." Double-click that.

The Mac Installer program will launch. Click Continue. It may take a couple of minutes for the program to tell you which drive you have selected for the installation. It will be marked with a green arrow. Click Continue.

This will bring you to the Easy Install window. If you want to take your Mac back to the original applications that come with it, just click the Upgrade button. But if you just want to install one, or just a few, of the applications, look near the bottom of the window, just to the left of Center, for a button labeled "Customize." Click that.

You should now see a window that lists many programs with checkboxes in front of them. All the boxes will be checked. If you want to just install QuickBooks, uncheck all the boxes except that one. Leave checked anything you wish to have reinstalled. Remember, if you've upgraded to iLife 06 and your computer came with iLife 05, you will overwrite the newer program. If you've had problems with the newer versions and wish to revert to the older versions, this is the way to do it.

Once the installer has finished, it will likely not require a restart, although your mileage may vary, depending on what is installed.