Sarabian,

I repaired disk permissions as you suggested. Although it corrected several permissions, it still showed up the spinning wheel and froze intermittently. After waiting a couple of days, I tried the next solution. I successfully repaired the disk (Disk Utility did find a minor volume block error and corrected it successfully). Unfortunately, within 10-15 minutes after I did this, it started to show up the wheel again. Do you have other things that I can try?

Sunrisetech, I tried the smart ultility (free trial), and my disk came clean. This was before I used the Disk Utility on the Mac OS disk.