Hello, I hope someone can help me. My iMac is not booting up. After I turn it on, it will only load up til the desktop wallpaper, and stop. The mouse cursor is visible on my screen, but there is no dock, no finder, or anything; the computer will not respond to any keyboard commands either. Please let me know if there is anything I can do. My processor is 1.83 GHz Intel Core Duo and my Memory is 512 MB 667 MHz DDR2 SDRAM.