My laptop lights turn on but the screen is pitch black

Monitor is connected (power and signal), turned on?

Corrupted operating system. Start over with a restore disc and if you do not have one buy one you will need it from the factory. Re-install the whole system over again. Insert the disc in the slot and power it on select boot from DVD or CD-Rom which ever you have. Follow the onscreen instructions. John

If your laptop appears to boot up and the hard disk LEDflashes, then the problem is probably a back light fault. This can be a faultyinverter or a faulty CCFL lamp. Please click on this link and follow myinstructions to identify the fault and possible fix :- http://www.fixya.com/support/r3598095-faulty_laptop_lcd_screen

Try connecting an external monitor and see if your see anything. If you can then most likely your LCD monitor on the laptop is dead. Also try FN+ the monitor toggle key to see if you can get video.

The problem could be that the video output settings don't go through the correct video cables. Here's how to reset those settings:

• Hold down the power button for 5-10 seconds until you hear two beeps; then let go.

First of all do you see anything on the screen, but really really dark, or is it pitch black. If you see something but it is black, then it is your screen backlit bulb and needs to be replaced. If it is just pitch black and nothing, then it mostly your inverter or a loose connection between your base to your screen since laptop tends to open and close alot.

when the screen is black and the power light is steadly lit, shine a flash light at the screen. if you can see something, the inverter board is bad and the back light cannot turn on. if the power light flickers, reseat the power plug and put your ear to the back of the monitor where the power plug is. if you hear a buzzing or any high pitched noises; the power supply is bad. use the macufactures warranty for repairs.

Depending on the pitch. humming noises are either a motor ie: fan motor or if it is very low a defective capacitor . Since you have the yellow band and the high pitched beep my fist thought is somthing defective in the power supply. Take it to an authorized servicer.

try sensing if your cpu fan is working, it is under the power switch side, you can see small exhaust slots, put your hand beside it and feel if some air is coming out when you turn on your pc.

When you turn you pc on and only orange light blinks, it means that no power was getting into it, it blinks because no electrical power is coming from your power adapter and the battery is drained. Check your power adapter cable, this is the very cause why your pc is shutting down. usually the wire from the adapter to the pc is faulty.

Over heating can cause a computer not to turn on, or turn off after a period of time.  You might have some dirt and dust in your fan that you need to blow out with canned air.

You might also try a laptop cooling plate:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2427205&CatId=215