Recently my computer has been acting up. I turn it on and I get no display - rather a black screen. It sounds like the computer is loading BIOS/doing the POST routine (ie it makes the noise my computer normally makes when I turn it on). This happened yesterday and after a few reboots it fixed itself. Now it will not fix itself after many reboots. The only thing different is I am not running on AC power (I left my charger at home, so I can't do anything until later)...Until then, any ideas?