I accidentally pressed the Moon button on my Dynex keyboard and the screen went black. The computer sounds like it is still running and I don't know whether I have a sleep mode enabled on my computer or not. I've tried pressing the power button for a short time but that doesn't wake it up, not does pressing a space bar or return key. I was in the middle of an entry in my financial software and I didn't want to just hold the power button to shut the computer off and then restart it. How can I get my display to turn back on?

SOURCE: I have a Lenovo 3000

What about removing the hard drive from the laptop and put it into sata box, to be USB external drive.
And then get out your important data, and format the hard disk.

and try again to boot???

If it doesn't work , try to replace the memory it might be the problem with the memory.

SOURCE: I have a IBM Lenovo ThinkPad T61. My laptop had

Even if you replace the CPU now, You will still need to replace the defective fan.

SOURCE: Blank screen upon startup

Try taking out the hard disk, plug in power and see if you have a display on your screen or external monitor. if same thing happen, try taking out the memory card. If you hear a beep sound it's a faulty mem. card, if no beep sound appears I suspected it's a motherboard faulty.

SOURCE: how do I wake keyboard up after putting to sleep (

try pressing the wake up key..

SOURCE: IBM T61 remains with dark blank screen but is on.

Connect it to another monitor,and see if it comes on. Your screen may be damaged.