My almost 2 year old MacBook, OS X 10.6.8, runs very, very slow after a little use, online and off...I gave it a 6 weeks holiday while I was away and when I returned it worked properly for 3 days, then began its slow decline into the little rainbow spinning and spinning. The sellers, Best Buy, where my guarantee runs out in 3 weeks, attempted to fix it, but seemed to do nothing and couldn't find any problem. There IS a problem, and its very frustrating. I feel like its a 90s version running on dial-up. Any suggestions? thanks.