Hello Community, I urgently require help with my MacBook. I'm a postgrad student with a thesis to write, and at the worst possible time my faithful MacBook has given up on me! It was working perfectly yesterday, until it kept freezing as I was browsing the Internet using Google Chrome, bringing up the pinwheel. I decided to call it a night and shut down in the usual way. It took an unusually long time to shut down. This morning, it has taken an hour to start up. First the Apple logo, then a blue screen displaying just a cursor, then my desktop background, then (very gradually) the Finder bar, dock, and icons one by one. Whenever I click on an App, or a menu, the pinwheel appears and it takes up to half an hour to perform the requested action. My MacBook is essentially unusable. I've tried restarting, but it simply starts the same process again, taking another hour to start up. This has never happened before, and it was working perfectly yesterday. Any advice would be gratefully received. Many thanks.