Software Update Crashes Mac Mini


I have 4 Macs at home. I have installed 10.4 on them all. If I update to 10.4.2 on my Mac Mini it crashes. The update runs fine but when rebooted it will either Kernal panic on start up or just stop during the start up process. All my other macs update fine.
I have even reformatted the HD and performed a fresh install but as soon as its updated –– Bang@!!!

Any ideas why??
Have you tried just downloading the 10.4.2 Combo Updater from Apple's website? I've found that whenever Software Update doesn't work for me when updating the OS, downloading the standalone Combo Updater does the trick. Just make sure that you don't have any extra peripherals connected to it except for the keyboard and the mouse when performing the update (either through Software Update or standalone). Having the extra peripherals connected while doing an update has been known to cause issues not just on Macs but on any platform.

Hope that helps!
An addition to nixgeek's suggestion.

Use 'System Preferences' 'Software Update' to obtain a list of suggested installations; go to Apple Downloads - and download the respective (Application, System, Security, etc.) updates [always download the 'Combo', in place of just the 'Update']; and then, install each one manually.

Backup the downloaded installers - for when you will have to reinstall your MacOS X version, and then the respective updates.