When I turn on my iMac (2007 CD2/Aluminum; 4GB RAM, 2TB Western Digital HD w/2 partitions, 500G+1.5T installed 2 years ago this month) running Snow Leopard (software up to date), I get the Apple Logo and the spinner. And it just sits. Spinning. No desktop. When I boot with the Snow Leopard Install and run Disk Utilities, the hard drive checks out OK (as a whole and each partition). SMART status is 'verified.' Running System Profiler does not reveal any problems. Also, I've disconnected everything except the Apple keyboard (and mouse). In other words, there's nothing suggesting that the drive itself (2 yrs old) has failed. No sad mac or missing disk icon at start-up. Just a spinner. I suspect something in the OS is out of whack on the disk, but I dunno. Any suggestions?