Q I started installing a system update on my iBook, then closed the screen. Now the computer won't boot up at all. Help!
AIn a better world, Apple's Software Update utility would have picked up the installation process when the laptop was awakened -- but in this case, it did not. Worse yet, the half-complete update left the system in a catatonic state.
You can fix this by using OS X's "Archive and Install" option. Get the system disk that came with the computer, pop it into CD/DVD drive, then hold down the "c" key as you turn the machine on. Keep that key pressed until you see a screen asking you to pick a language. Choose English, then click the first two "Continue" buttons until you see an "Options . . ." button at the bottom of the Mac OS X installer's window.
Click that button, then choose "Archive and Install." That will do something usually impossible in Windows -- put a brand-new copy of the operating system on the computer while leaving your files, settings and programs intact. (You can save disk space by clicking the next screen's "Customize" button, then declining non-English versions of your software and fonts, unneeded printer drivers, and trial copies of software.)
Once this process is done, your computer should run as it did before, but with a "Previous System Folder" on the hard drive. If you had any custom desktop backgrounds or fonts installed, open that folder's Library sub-folder, then open its Desktop Pictures and Fonts folders. Drag their contents to the same places in the new System Folder, then delete the Previous System Folder.
Now have Software Update look for any necessary updates to your system -- and this time, let it finish the job uninterrupted. That applies to system-software updates on any computer, regardless of operating system; when it's replacing or deleting core system files, don't interrupt it.
-- Rob Pegoraro
Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 firstname.lastname@example.org.