Hello. My wife's Macbook is running VERY slow. She is not a power user - basic surfing, email, etc. The specs on the laptop are pretty good - Core2 w/ 1.5 gig ram. The problem is the round beach balls pops up often and just cripples the computer. I have tried to clean the machine; however, I have had no luck. Do I need to reinstall the OS? Thanks in advance!