After 10.5.6 update MBP early 08 crashes in an strange way

Question

The update went through smoothly, but when I used the MBP again, something strange happens:
After a few minutes the mbp was useless. I could see the dock, I could klick the dock but allthough the icon behaved like I was klicking on it nothing happend, so no jumping icon.
Also strange: cmd+tab does not work, it just makes a "boing" sound, no list of open apps.
Add this: The list with open apps (cmdaltesc) is also empty.
Restarting is not possible, the popup asking what to do when I press my power button appears but after selecting reboot nothing happens.
I made a new account to watch some movie. So I started Quicktime and after, I don't know, 15 minutes, I checked and the info bar above was transparent, after a while it was gone, also the dock disappeard, not always but quite often.
I am on a busniess tripp (Hopefully I don't need the mbp) and will be back on weekend. If I can't solve the problem I have to reinstall...
Edit: I already removed everything out of the autostart and unused system prefs.
And iTUnes tells me, from time to time, it can't save the library because the rights are not given or the volume is not av.
Message was edited by: christof.lapd

Answer 1

I kind of fixed my problem with the "Install and Archive"-Option. Worked out well (And smooth!)
http://support.apple.com/kb/HT1710