It sounds to me that your problem begins to appear AFTER you have been working for a few hours. Are you accessing the internet between the time you start your computer up and the problem appears? Have you checked your internet cache file when the problem starts to appear? Overloading your cache files can slow your computer down. Another thing to look at is the state of your data configuration on your hard drive. If you haven't defragmented your drive lately, you may be having access problems to the data when your computer has to search for resources. My last suggestion is to zap the PRAM and rebuild your desktop directory. Hold down the Command, Option, P, and R keys while starting up to zap the PRAM. Continue to hold these keys down until you hear the start-up chime at least three (3) times. Then release the keys and finish the start-up procedure. To rebuild the desktop directory, restart again and hold down the Command and Option keys during the restart, then follow the on-screen prompts. HTH, Ron