I was searching my applications and out of nowhere EVERYTHING froze and a rainbow colored ball appeared and began to spin. Entire computer locked, even tried to go to the top menu to click the Apple logo and select shut down and it wouldn't let me. Finally was forced to press power button AND hold it for 10 seconds before it finally shut down. I seem to be having more problems with the Mac than I did with Windows. What's causing this to happen and how can I solve the problem?