Earlier this week (2/17), I downloaded the weekly software updates. There was an update from Quicktime, a security update and something else that I can't remember. After the required restart, my computer (Power PC G4, 450 MHZ, OSX 10.4.11) started "hickupping" every minute or so. If I am working in any application, it bumps me to the finder. If any folders are open on the desktop, they close. when this happens, my desktop is also slightly altered. (the hard drive icon will jump to the default position) I have run a couple of repair utilities and fixed permissions and found only a few minor problems. As I write this, all my desktop icons have disappeared. Is there anything I can do short of system reinstall?