Hi Hema Ramani,
Welcome to Dell community!
May I know if the red tint is seen at the Dell logo screen that appears when you first power on the laptop?
Refer the following link for instructions to run the LCD built-in diagnostics: http://dell.to/16eAVHe
Please check if the red tint appears during the diagnostics. Also, if you have an external monitor, connect it to the laptop and check if the display is fine on the external monitor.
Do let me know the results.
Thanks & Regards
Even when the system is in the turn off state i can able to see the impression of the red tint.I didnt know whether it is an mark on the screen or any virus.pls suggest me.
This is a physical hardware failure.
if it shows up on external monitor then its GPU/Motherboard Related. If not its LCD related.