My Dell Mini turns on, goes to the Dell logo screen, after progress bar loads, it goes to a black screen with a blinking underscore in the upper left hand corner. Nothing happens, keys don't do anything. If I plug in my usb drive, I can press F12 during the Dell logo and choose diagnostics, then, I can choose the USB drive or the hard drive to boot. If I choose the hard drive, everything works like normal and snow leopard loads. If I choose the USB drive, Snow leopard installation starts. How can I get it to start like normal? Thanks.