This issue could be due to presence of static charges or internal hardware malfunction of the notebook. To isolate the exact cause of the issue, perform the steps provided below.
Step 1: Hard Reset
To perform a hard reset, please follow the steps listed below:
1. Unplug the AC adapter from the notebook PC and remove from any port replicator or
2. Remove the battery from the notebook battery compartment.
3. Press and hold down the power button for about 20 seconds.
4. Insert the battery and plug the AC adapter back into the notebook PC.
5. Press the power button to turn the notebook PC back on.
This will discharge the static charges from the notebook. Now turn on the notebook and check for the issue. If the issue persists, then remove and reseat the memory modules of the notebook and check for the issue.
Step 2: Remove and Reseat the Memory Modules
You can refer the service manual provided below for information to remove and reseat the memory modules of the notebook.
Refer page no: 52 & 53
NOTE: PDF manuals require the Adobe Acrobat Reader for viewing and printing.
Further, if the issue persists after performing the above steps, then the issue could be due to hardware malfunction of the video card or defective LCD display screen of the notebook. Hence, I recommend you to connect an external monitor to the notebook and then check whether the display works fine on external monitor or not.
Step 3: External Monitor
You can follow the steps listed below to connect an external monitor to the notebook.
Turn off the notebook.
2. Connect the monitor cable from the external monitor to the monitor port on the rear of the computer.
3. Connect the monitor to a power source and turn it on.
4. Press the Power button to turn on the computer.
At this time, please follow the instructions mentioned below for switching the display to the external monitor:
The notebook's video card supports three modes. Built-in screen only; external video only; and both on simultaneously (mirrored). If you're not seeing the image on the desired device(s), the notebook's video card is probably in another mode. Press FN + F4 to cycle through the display options: Notebook display, External monitor, both.
If you press FN + F4 once, the external monitor will display & there will be no Notebook LCD display.
If you press FN + F4 twice, the external monitor will display & there will be some shading on the Notebook LCD.
If you press FN + F4 thrice, both Notebook LCD & external monitor will display.
If the issue persists on the external monitor, then this could be due to defective video card on the notebook. However, if the display on the external monitor is fine, then the issue is with the LCD display panel of the notebook. In either cases, the notebook requires a detailed onsite diagnosis by a service technician.
I believe the information provided would be helpful to isolate the issue with your notebook.