I'm stumped. The "genius" told me Mavericks and other software, etc. had rendered my 4 GB of memory insufficient. He verified that the HD was fine - my original guess, since it's on it's third HD. And, he suggested upping the memory. I did. The machine now has 16 GB of DRAM. But, it's a slug. I see that damn beach ball way (!) too much. I restart the machine a couple times per day. Web pages are ridiculously slow to load (pinging about 27 mps). Lots of other apps are slow too. Oddly, opening System Pref's may be the slowest native app/program - it can take 30 seconds to even respond. Any ideas? Thanks!