My Dell Gx270 don't Display and powder yellow led is on and my keyboard leds num led capslock led and scroll led trun on and turn off again and again.

Try CapsLock or Num Lock or Scroll Lock.

Hi, If you are using a keyboard that is wireless im sure you just have to change the battery on the keyboard.
However if the keyboard is connected to your CPU, then depending on your keyboard model, you may have to turn F LOCK (F Lock Light on) to access system key commands if they are labeled on the front of the keys, such as num lock , scroll lock and print screen.When you click on the Flock, the lights are either supoosed to click on or off.
view the keyboard status lights by using the On Screen Display (OSD) option, Ensure you download the software ,
from your start menu do a search for your keyboard, on th key tabs setting,
its important to make sure that the correct model number is entered,
double click on the light you wish to change, in the Reassign a Key wizard,
clear the Displays (key name) status on the screen check box to disable the on-screen display, or select it so that a check mark is in the box to enable it, and then click Finish.
HOPE THIS HELPS.

It certainly does indicate motherboard issue, sub out the ram memory one at a time and test, if no change! the laptop needs to be checked out for motherboard problems.

Hi, just pull out your memory card and clean it with an eraser. And insert it tightly again and don't forget to clean also the memory bank.

Hope it will help you.

How many blinks between pauses if there are pauses? Look at this chart.
Number of Blinks or Beeps Location of Blinking LEDs Component Being Checked Error Condition Continuous glow Battery power LED Battery The AC adapter is attached and the battery is charging, but does not yet have sufficient charge to power the notebook. 1 Caps Lock/Num Lock CPU CPU not functional 2 Caps Lock/Num Lock BIOS BIOS corruption failure 3 Caps Lock/Num Lock Memory Module error not functional 4 Caps Lock/Num Lock Graphics Graphics controller not functional 5 Caps Lock/Num Lock System board General system board failure 6 Caps Lock/Num Lock BIOS BIOS authentication failure Continuous blink AC power adapter LED Power adapter Insufficient power

Copy and paste this link into your internet browser for the service manual for your laptop.
http://support.dell.com/support/edocs/systems/vos1510/en/SM/html/trouble.htm#wp1092170
The star icon (*) means flashing LED, the bold circle means on, the circle within a circle means off.
The LED's that they are referring to are the NUM, CAPS and SCROLL.
It appears that you have a problem with your LCD. Try connecting an external monitor to your laptop. If you get a display then your LCD display panel needs to be replaced. If no display then your motherboard needs to be replaced.

Most keyboards have a LED lights that indicates when the CAP lock and the NUM lock has been pressed.

remove external peripherals. remove battery. use ac adapter alone. when u turn on laptop check the lock leds. what is the status of the lock leds (numlock) (capslock) (scroll lock)

they continue to blink every 5 seconds until you turn it off? It should blink all lights upon powering on but then remain off,

press shift + num lock and see if works. you should have a green led under the display. when press SHIFT + NUM LOCK , the green led state should change