HOW TO DO THIS...inverter cable. It either needs to be re-seated or replaced.

check and make sure your video card is seated properly if it is my best guess without doing any testing is that your video graphic card is broken

1) Wrong LCD screen

2) Video Cable (LCD Cable) is not connected tightly.
Motherboard side, or LCD screen side; or both.

3) IF, a screen Inverter is used, the small cable from the Video Cable, that connects to the screen Inverter; is not connected, or has a loose connection to it. (screen Inverter)

4) An LCD screen, and a screen Inverter are a Matched unit.
If it's the wrong LCD screen......................?

5) IF, a screen Inverter is used; the diagnosis was wrong, and the LCD screen was replaced.
90 PERCENT of the time, the fault is a bad screen Inverter.

A) Laptop's LCD screen uses a CCFL, (Or more than one), for a Backlight; the laptop uses a screen Inverter.

Diagnostic flowchart leads from Graphics Chipset, to Video Cable, to screen Inverter, THEN, LCD screen.
Expensive LCD screen was replaced, instead of the actual part that needed replacing;
Video Cable: $9 to $22
Screen Inverter: $9 to $22

LCD screen: $60 to $245

B) Laptop's LCD screen uses LED backlighting, and does NOT use a screen Inverter:

Diagnostic flowchart is;
A) Video Cable;
A Video Cable should have it's connections PHYSICALLY checked.
You have to try to push the connectors in tighter.
Visual inspection alone will NOT do.

Making sure the Video Cable connections are tight, and this does not fix the problem, then the Video Cable needs to be removed; and every wire in the Video Cable checked for Continuity with a multimeter set to OHM's. (1K)

Not feasible, then take the Video Cable down to the nearest small computer shop; and have the resident tech check it for Continuity.
Should only be a few bucks.

Or just replace the Video Cable.
(Parts changing I know, but...........?)

Primer:
An LCD screen cannot produce light. It needs an additional light source.
A Backlight is the additional light source.

A Backlight can be a CCFL, (Or more than one), or a series of LED's.
(Light Emitting Diode)

A CCFL is a Cold Cathode Fluorescent Lamp. (Bulb)
Similar to Fluorescent lighting used in homes, and businesses; but on a MUCH smaller scale.

Average thickness is 2mm. That is a little large than 1/16th of an Inch.
Average thickness is almost as long, as the LCD screen is in height.
View the last 8 photos,

http://www.laptoprepair101.com/laptop/2007/12/09/replace-laptop-backlight-ccfl-lamp/

A screen Inverter is used to convert the power, (Electricity), from the laptop; for the LCD screen, and Backlight.

As previously stated, Backlighting that uses CCFL, uses a screen Inverter.
LED backlighting MAY, or MAY NOT use a screen Inverter.
When the LED backlight technology first came out, it seems some did use a screen Inverter.
It also seems as the technology advanced, LED backlighting does Not use a screen Inverter.

Regards,
joecoolvette

Hi,
It has to be opened. The inverter cable needs to be re-seated or replaced to fix it.

Hi,
This is a problem with the inverter cable. It either needs to be re-seated or replaced.

Verify that the Flat VGA cable from the laptop to the screen is securely locked into place by wiggling it slightly, then seat it and use the original tape to secure it in place. Then follow that ribbon down to the motherboard and make sure it is firmly seated in the internal VGA output socket. Secondly, make sure your white and pink backlight power cable is connected to your inverter while taking care not to bend the inverter. these are fragile and break quite easily. Then check the opposite end of your inverter and make sure the power wire is securely connected (snapped) into place.

if you replaced the screen, might be a pinched wire,or loose connection to the mobo (motherboard)

It's probably the wrong screen, cable ,or inverter; in spite of what the repair shop tells you .
Also, sometimes the cable gets pinched if not installed carefully, or the cable connector may need to be re-seated.
Is your laptop a Dell Precision M60 ? I'll see which screen it's supposed to have.

First thing is to check the connection on the back of the computer and make sure your video card is seated and the cable plugged in.

It does sound like an inverter board on the monitor. Something you may need to take it in to a shop. The problem is, with a smaller monitor, it might not be worth it.

If you are fairly handy, the inverters can be found online and replaced.

The other thing to try, if you have one, try another old monitor, just to eliminate the video card in the computer.

An inverter repair might cost you around 100-150 plus parts.

you may plug off remote monitor power on to see carefully is there normal dark picture on your lcd screen,
!) lcd dark but there is pcture on the screen, it means the back lights inverter damage(which in the lcd lid and downside of lcd panel), or lamp damage (in the lcd panel), have to replace new parts
2) no any picture and dark panel, you may check lcd signal cable plugs are right seat in the sockets (which located between the back of lcd panel and motherboard), also check the inverter cable same thing (it merges in LCD cable) . it is better replace a new cable (most cases are cable disconnection somewhere)
is this helpful please feedback when you checked, iwill tell you what you can do next, thanks

Either your video cable needs to be re-seated,or your inverter is going bad.To fix either one you'll have to open your screens plastic housing and also remove the piecce of plastic where your power button is and lift out the keyboard.Re-seating the cable won't cost you anything,if you do it yourself.An Inverter will cost you roughly $60 plus shipping.