I have Dell Latitude D610, yesterday I used and shut it off properly but today when I boot it, the screen was bright for the moment but then it turned blank but power light and other lights were still on like wifi and num lock lights. I saw the screen carefully it was showing desktop but there was no light that I can use it.
I am worried, I reboot many times but everytime same condition.
What to do? I will be thankful if you help me.

From my experience with dells, it is most likely the inverter/inverter cable.

The cables range from $10-$30 and the Inverter is around $100 (For the model I was repairing.)

You can confirm this by plugging the laptop into a monitor using the vga port.

If I plug my laptop into a montor using VGA port and what if the monitor shows perfect result? what will it mean?

If the vga displays an image - It's most likely the inverter/cable.

If not, it's most likely the on-board gpu/motherboard (Something more serious)

Is your Dell still under warranty? If so, get in touch with Dell, don't rush into spending any money.

As Beginnerdev says, it may be the Inverter, but there is also the possibility that it could be the Backlight.

Something to try before spending any money... I personally have never seen this work, but it's reported to be successful by some. While the laptop is off and power cable disconnected, remove the battery and then reinsert the power cable and turn on the laptop. (without the battery) Does that make any difference?

This job involves, whether Inverter or Backlight, careful disassembly, and even more careful reassembly.

I tried that battery removal method but it didn't work out.
one thing, today when I boot up my laptop it shows the same situation but after few minutes it lights up and shows the message of windows recovery,but when I restared again the it was the same!!

This might be dumb to ask but is the screen brightness turned down. if not my advice is get it back to dell with a note saying how disappointed you are as all your family uses dell for many years etc they are quite good at giving you an extension on the warranty. Angry letters of complaint not so much

I increased the brightness as well but no use of it, and my laptop's warranty is over :(

Do you have technical knowledge on how to disassemble and repair your laptop?

Or, do you know some one who does?

To replace the inverter, it requires complete disassembly. (Including the LCD enclosure.)

My advice would be to dissassemble it, check the cable, then make your purchase. This will negate the uneccessary spending of money.

The cables are fairly cheap, but the inverters can be quite expensive.

I have changed my LCD, it costs Rs. 3000,
thanks for helping me :)