Did you look at the screen with a flashlight to see if there is a faint display on the screen? It is not uncommon for the backlight to fail, usually the result of the display's power inverter failing.
Also, while I know what steps I would take to declare "I've tried everything", I have no idea what steps you have tried (I'm assuming a reset at minimum) so actually listing the steps you've tried can help here
hi thank you for your answer. I have checked there is no backlight. I used external monitor also. Bt extrnal monitore also showing same issue. cleaned ram and reinserted it .tried to put another new ram also. but the issue same.
Does the laptop feature dedicated graphics? Can you get into BIOS at all?
If no to the above, I'd be inclined to believe the graphics is bad - if it has dedicated graphics there are repair options.
If the laptop does not have dedicated graphics I'd think replacement would be my preferred option
Full model number can help immensely here since I need that to see specs (helps to know what hardware I'm considering as possible issues)
Two things to try before the third (although I'm leaning toward the third here)
Try cycling the display by pressing Fn+F7 keys also try the Display Off key
See if any display in BIOS. To access BIOS, rapidly tap the delete key after starting the computer (you can't tap it too much) if no display then, see below - if you do get a display in BIOS let us know
If the above doesn't work, I'm going to recommend looking into having the GPU "reballed", it is a specialty process that few shops have the ability to perform but it seems to be what's needed. It may be a little expensive and depending upon your location, the laptop may need to be sent off to have the service performed. Another service that may work is known as reflowing but I won't recommend that since it's usually a very temporary (if successful at all) fix - I've personally only seen one graphics card last an entire year after a reflow (I'd say the average is a few months). While reflow is an option, I would not recommend it here
Although it shouldn't need to be said, there are some very flaky companies out there, I'll suggest researching the company thoroughly before sending off your laptop (if that's what's needed) for repair, call or talk to them personally, ask questions to get a feel for their customer service level also - not everyone is a computer guru, don't be afraid to ask "stupid" questions