Factory restoration of a computer is a process that wipes the computer's hard drive of all files and folders and then reinstalls them. This process is used when the computer is dysfunctional due to malware or a virus, or if the user simply wants a clean slate for his computer. A factory restoration literally returns your computer to the state it was in when you purchased it, with all the factory settings and software. If you're interested in restoring your Mac PowerBook G4 to its factory settings, there are just a few instructions to follow.
Back up any important files already on your G4's hard drive. A factory restore completely wipes the system of all files you've created so, if possible, make sure you have another copy of all your files, images, music, etc.
Connect your G4 to its charger. Restoring the computer is a delicate process that erases and reinstalls the most basic and important files of your system. If the computer runs out of battery before the restoration is complete, files may be damaged or left uninstalled. The result of this varies from having to restart the process completely to permanent dysfunction of your computer. Play it safe. Make sure you have plenty of battery left and the computer is plugged into the wall.
Locate your Mac OS X Install CD/DVD. If you have lost the original disc or never received one (a common problem when purchasing used computers), there are a few options to consider. The first is to ask around; if you have friends or family with a Mac computer they may still have their CD. It would be usable on your computer. If this option fails, look online for a download of the installation CD. Some sites offer installation CDs for all kinds of computers, including the G4.
Insert the install disc into your computer's disk drive. Once visible, click the "Install Mac OS X" button. Follow the on-screen prompts to set up your computer preferences and begin installation.
Select a destination disc for the installation. This is typically the "Macintosh HD" icon. Next, click "Options," and follow the rest of the on-screen prompts/instructions. After this, the software is installed. The computer should reset itself or can be manually reset by holding down the power button twice.