Here we go again....10.6.7 doesn't kill anything

In the words of the famous fictitious spy series protagonist, James Bond, "Always have a backup plan." That is true regardless of what computer you have, anytime you install anything new, you should have at least two backups present. They can be printed or digital, but the point is, you don't have to recreate anything from scratch. 10.6.7, like any update is there to improve or add features of an operating system. It is not there to fix pre-existing conditions that make a system slow, or inoperable. If your system is unhealthy, backup, or use data recovery, and then ask for help here how to solve your problem. Make sure all your software and hardware is known to work with the update before applying it. Ask here if uncertain first. And remember updates don't kill anything, they only shed light on hardware or software that may already be marginal because they are sensitive to that.