I never had a problem with my 20" iMac until the other day when I installed the graphics firmware update. Since then my computer has had all sorts of problems. When using my mouse for instance, it will sometimes randomly jump across the screen or suddenly bring up the dashboard without me clicking on anything. Sometimes my dock won't even respond when I pass my mouse over it. I will click on programs and they will boot but it won't move. Also, my hot corners don't work some of the time. The only way I have found to temporarily fix it is to shut down my mac and start it up again. I thought this update was supposed to help, but it's made things much much worse for me. Does anyone have any suggestions?