I have an iMac 800 MHz G4 (waiting anxiously for a new model to be released) running OS 10.3.9 which has performed faultlessly until now. Clicking on an icon on the desktop causes all icons to disappear from the desktop for a couple seconds before they reappear. The clicked icon does not open. At the same time that this started happening, several applications such as Word, Entourage, iTunes, Quicktime, GraphicConverter, would open on request but then immediately quit. In the case of Entourage I am able to select an email but the application would quit as soon as I tried to scroll. Safari and Firefox are working as normal, as is Apple's Mail. I have tried repairing permissions, update prebinding, deleted Finder preferences, all to no avail. I have changed users and still have this problem. Has anyone had a similar experience?