On 10.2.7 and Lion has just been an enigma of trouble on my Penryn Macbook Pro. After the first install ran into problem on the upgrade with apps crashing. Went into system prefs and saw a number of old stuff had been carried over. So killed everything there old. The system will run fine for a day or so then it starts locking up, movement becomes slow or next to impossible. Then the inevitable, force quit one application. Done. Watch as another application that's open goes to "not responding" then another and another until you can finally reboot. This has been going on for weeks. Macbook Pro 2.4 ghz with 4 GB Ram. Just had the logic board repaired and it still happens over and over. Snow Leopard was fine and almost all earlier system OS releases never acted like this. Yes, after the initial upgrade, I did a CLEAN INSTALL. Yet, Lion still goes into this overheated, can't move around and then application after application crashing. It's awful and I don't get it. I've been using Apple OS for decades. When Lion runs fine, it's fine then suddenly it's hell. You are forced to quit one application after another as you watch the force quit red "not responding" go from one app to another. Not good.