After updating to 10.4.11: Mouse "lacks behind"

Hi everyone!

I installed 10.4.11 yesterday, but unfortunatey, my MBP 2.4GHz does not run as smoothly as before. Here are the details:

After the upgrading process, I returned to my MBP and saw on the screen, that the "DashboardClient" had been shut down unexpectedly and whether I want to submit a report to Apple. However, I couldn't do anything anymore, because the screen was dark and an instruction told me to restart my MBP by pressing the on/off button for 5 seconds. This I did and at first the MBP seemed to work fine.

However, when I'm working with my MBP, for example moving the mouse, typing text, scrolling etc., the MAC sometimes stops to display any changes (e.g. it does not show the incremental text that has been typed or it does not show and last mouse cursor movements) until after a second or so. Then the incremental text is displayed or I can move my mouse cursor again. This really gets on my nerves...

Does anyone of you have a similar problem or know, how to fix it??

I really appreciate you help! Thanks!

Best regards
Matthias