The computer was on, checked the weather channel, walked my son to school and walked into my office to a black screen. Tried re-booting, I get the Dell screen and then back to the black screen, go to BIOS and try to change reboot sequence, did not work. I can't get into Safe Mode, lets me select it, but when I hit enter goes back to black screen. Any suggestions on how to fix it???? I'd appreciate any help 