My mid 2009 MacBook pro has suddenly developed a crippling problem. When I use safari 5.1.7 after 5 or so minutes everything locks up. I get the spinning beach ball and cannot click on anything until I force close safari. Literally the whole machine dies. This always happens after what seems like the same time period - everything is fine then my laptop becomes unusable. Can someone help because it's driving me insane. I've tried the cache and resetting safari and deleting the plist but it won't work.