Q: Dreaded color wheel!

You need to uninstall Clean My Mac > http://macpaw.com/support/cleanmymac2/knowledgebase/how-to-uninstall-cleanmymac- 2

That's the last thing you want to use on your Mac for the spinning beach ball.

If this is a 2007 iMac, it might be a good time to run the Apple Hardware Test

Apart from anything else you do to fix this, make sure you're keeping regular backups, because one option on the horizon is hard drive failure or some other hardware failure. Of course that is always a possibility.

Have you repaired permissions (using Disk Utility)? Reset "Perimeter RAM?"