Computer turns on but screen stays black

check also your processor

Try connecting to an external monitor and see if that works. Is the hard drive activity light flashing at all?

If your laptop appears to boot up and the hard disk LEDflashes, then the problem is probably a back light fault. This can be a faultyinverter or a faulty CCFL lamp. Please click on this link and follow myinstructions to identify the fault and possible fix :- http://www.fixya.com/support/r3598095-faulty_laptop_lcd_screen

Have you accidentally turned off your lcd? Some laptops have a shortcut key for turning off the lcd, usually the FN key combined with the function keys (F1 to F12). If you have a spare monitor and your laptop has a VGA output, try connecting your laptop to another monitor. If it shows up, then you may have a faulty lcd.

Since it sounds like an issue with the Power first try to release flea power.Disconnect the charger,remove battery,press and hold down the power button for 30 seconds.Reconnect the battery and charger.Turn on system and check if it turns on. For further help please check Dell Inspiron 1525 Manual. Also confirm if the light on the charger stays on,when connected to the system.

Do a hard reset by turning off the computer and removing the battery and unplug the AC adapter. Without any power source, press and hold the power button and put everything back after. Power on the computer again, if it does not work, try to connect your laptop to an external monitor. If it shows some display it means that the LCD monitor of your laptop has gone faulty.

1. take out the memory
2. turn on again without memory (you should hear long beep sound) and turn it off again
   
3. clean memory using eraser (better if you have spare memory to replace it)
4. now try again
   
5. if not working, checks whether the work properly? and clean the fan from dust. and try to switch it on again.

I look forward to hearing further.

take your computer to your dealer and send it for repair.

The problem is most likely the inverter for the screen.
actually to see if that is the problem you can try to put bright light to the screen and see if you barely see the picture.

It sounds like video card problem. Bring it to a repair shop.

Repaired! This sounde like a fuelty screen or screen inverter. To check this, connect to an external monitor, if the external works properly, then it's the screen or inverter. If the external doesn't work, let me know and we'll run the problem down to a more indepth (internal) trouble shoot.