In the past few days, my iBook G4 got awfully slow. Beachball showing up all the time, since login. It takes 3 or 4 times longer after login before I can start working. I haven't done anything special, or installed new software. The last thing I installed is the 10.3.4 update, but everything was fine and fast after the installation and for the next couple of days. Everything seems normal on Activity Viewer. Where should I start looking?