When the colored spinner comes up, everything locks up - cannot escape.

What are you doing when this happens?

This is a Mac freeze usually caused by a bad file permission, broken internal file link or dependency. Try opening "Disk Utility" under "Utilities" in "Applications" if you can not get there insert the OS install disk that came with your computer and boot holding the "c" key.
Select a language and you will get an install screen with a menue select Utilities and Disk Utility.

Once in disk Utility select the Macintosh HD and under First Aid run Permission Repair. This more than likely will fix the problem if no let us know.

If the problem happens when you launch a certain program you can uninstall it, but run the permissions repair before uninstalling programs.