Hi Arasananthan N,
I regret for the delay.
If the display on the external monitor is fine, the issue might be with the LCD on the computer.
Did you try running LCD diagnostics on the computer? If not, run LCD diagnostics on the computer and let me know the status of display during diagnostics.
Also, check the display in BIOS. Restart the computer and tap F2 at Dell logo and check the display.
Awaiting your response!
