Hi! I have a 2.4 Ghz Core 2 Duo 20" Aluminum iMac. I often have a problem with my mouse not working when booting. I turn the computer on, and more than half the time, the mouse infrared thing on the bottom turns on then goes by the time the blue screen comes. Then I have to reboot again, and usually about 3 times before it finally works. I use the Mighty Mouse connected to the Apple Keyboard connected to a USB extension cable. I tried it without that but it still didn't work. Any suggestions would be great. If none of them work, I will contact AppleCare as I am still under warranty.