You did not say what update you attempted/made, but assuming it was the OS X 10.6.8 update the standard "fix" would be to redo the update using the OS X 10.6.8 Combo Updater. Of course that is a bit of a trick to accomplish on a machine that won't boot. The simplest work around to that would probably be attaching the non-booting Mac to another booting Mac with a firewire connection, booting the non-booting Mac into firewire target disk mode by holding down the T key during the boot. Then you can run the install from the other computer.

Just to be on the safe side, I would run Disk Utility > Repair Disk before attempting the reinstall.


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honestly, and you'll find people who are eager to
fill your head with information"
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