Dual G5, OS 10.3.3 During a software update a few days ago (Security Update, FCP, Livetype, etc.), my computer hung during the optimization part. I had to do a hard restart, and when I did, I got a kernel panic. This happened every time I restarted, always occuring after the desktop appears and the background applications launched. I started in Single User Mode and did fsck -fy, it fixed a few things, fsck again, no problems --> restart --> kernel panic. I restarted from the Panther CD, and I got a kernel panic during the disk first aid. This really surprised me...and worried me... I started in Firewire Target mode and used my Powerbook to run Diskwarrior and Norton. They found some errors and corrected them. I fixed permissions. Upon restarting, things worked for a little while, but I then got a kernel panic. I then reset the CUDA and PRAM --> same thing. I ran Apple's Hardware test - no problems. Then I did a clean erase and reinstall of Panther (via Target Mode). Things worked for a bit, but I then got another kernel panic. I then pulled the 4x512 Crucial sticks I had in there and put back in the original 2x256 Apple memory. Things went smoothly this time - I used the computer all morning without problems - so I figured it was bad memory. But when I came back just now, the jet engines were flying...another kernel panic. So why is this happening? Why did it start after this failed update - especially since things had been flawless for months... Why the panics when I boot from CD? The memory does not seem to be the issue. Firmware? Any other thoughts before I lug this thing to the Apple Store?