Honestly, I feel helpless. I was used to this when I had Windows, especially Vista, but I never got any problems with Mac OsX until recently. It's been happening at least twice a day. I'm browsing the internet, listening to some music, and a couple of small applications are open (preview, stickies, iTunes) nothing more than that. Suddenly Safari blocks, I get the rainbow cursor, I try to move it around to force quit or try to use the Finder, but then BAM, the whole system stops responding, and I'm left with only the mouse cursor working. All I can do after that is turn off, then turn on. I've also been experiencing some lag in my iTunes, where the music stops for a couple of seconds. I have a Macbook pro, 2010, i5 2.4, 8 gigs of ram, Lion 10.7.1 full updated (installed over Snow Leopard). Note that during all these crashes I always have at least 3 gigs of free Ram. Help is appreciated. I'm starting to think about formatting everything, and performing a clean Lion install, though it's hard for me to do this for the moment, because I got so much work to do on my computer.