I have a HP Pavillion computer that went down after power-up. The computer shows the blue "HP Invents" screen for only 30 seconds. There is no beep. I did a CTRL-ALT-DELETE and the screen appeared for 30 seconds. The ESC and F10 keys work but the F11 key is not functional. Currently there is a blank screen with a blinking" cursor in the upper left hand corner. The LED below the main power switch is also dead. I am not sure what steps to take. Thanks.