Well for teh power down, I dont know other than maybe a service is not getting killed properly. Even at that -- it should still halt. Try getting me the info on what it says as it iomproperly shuts down, and I can help.
Root configuration -- I had this problem a bit ago with KDE 2.1. KDE 3 however has been behaving quite well and the solution I normally would give is update to the newest revision. However, we know that that wont exactly help First step I would reccomend is to see if the KDE config files are allowed to be modified. If so, try editing them by hand and see if the cange is applied. Once you get to that poiint, there is more than likely a goofy setting that is preventing you from saving you changes thru Kontrol Panel. If all else fails, vape your /root/.kde/ directory and start fresh. That happened to gnome a few times on me. One of the files got corrupt and required my user account to get a fresh gnome directory.
For your video -- check the size settings on the monitor. I recall back when 15" was gargantuan, my monitor when the size and position of the view area was wayyyy off, there would be very odd graphical mutations.