My mac crashed (screen went dark and a black square appeared saying I should restart my computer, which has happened a few times before recently) I restarted my computer by holding down the power button. But unlike usual my computer restarted, by just showing the time and UK flag in the top left corner of the screen (not in a bar). There is no hard disk icon or partition icon, the toolbar at the bottom of the screen works, and I can open movies or photoshop files etc by opening the program and clicking: 'file>open' etc, but other than that, I can not browse my hard disk or open finder. If I click on the finder icon in my menu it says: 'The application "(null)" cannot be launched. -43' and no matter how many imes I restart my computer I cannot find finder! Any suggestions??