I turn on my Gateway LT27 and get the message "No bootable device - Please restart system". If I hit F2 to get into setup mode, it just hangs. Once in a while, when I reboot, I randomly press a bunch of keys on the left side of the keyboard and it miraculously takes me into windows and works fine so the disk is ok. When I first had the problem, I could still get into F2, but after trying different options there, I'm pretty sure I messed things up and removed everything from the startup list. What to do?