Very slow at start up. Then by passes my log in, goes directly to my desk top. Then takes 5 minutes before I can click on anything. After 10 to 15 minutes it freezes up then I get the spinning color wheel. It will spin for hours if I let it. I have to turn the computer off manually. I have ran disk utility, updated, and even reinstalled Snow Leopard OSX. Nothing has worked. HELP!!

Insert your OS DVD and start while holding the "C" you will be able to choose Disk Utility from the menus when the box appears for you to start the installation. In disk Utility run disk Repair and Permissions repair. If there is a correctable error on your hard drive this should fix it if you get any error messages write them down and contact Apple if your unit is under warranty or Apple care.