Dell D430 Screen Flickers

This is a pretty interesting problem.  Are you using the AC adapter that originally shipped with the system? If you have a spare AC adapter does it cause the same problem? Since the problem doesnt happen without out the AC adapter it may simply just be a bad adapter.

Assuming the AC adapter is fine, connect an external monitor and see if it flickers while using the AC adapter.  If the image on the external monitor is fine then it will be some time of interference with the LCD.  You may want to check and make sure that the data cable to the LCD panel is firmly seated.

Let me know what you find out.

TB

Hello.

Thanks. I unplugged the Battery then it works fine with the same AC adapter and even with another one. When I am using with the battery and AC adapter both at the same time then it start flicking again.

Another important thing is when the battery charge remaining less than 90% then it starts problem, otherwise it works fine even with battery. I am going to check after the change of battery with another machine let see the result. I am thinking might be the problem is in Battery. What you say?

Since you dont have the problem at all as long as the AC adapter is disconnected my thoughts would be that the AC adapter is at fault.  Obviously if you connect the battery to another system and it starts having the problem then yeah I would think it was the battery that was at fault.

TB 

Hello.
I tried after change the Battery but the problem is still there. Then I change HD with another Machine(Same Model). This machine works fine but once I pluged in AC Adapter then it reboots automatically. I had tried with different Adapter and also update BIOS and Chipset driver but no sucess. It restarts in 3 to 5 minutes, no blue screen etc. What could be the reason?

Regards,
Afzal

So to make sure that I understand the problem, with a different hard drive installed as soon as you connect any AC adapter the system reboots?  While with the original hard drive all that changes is that the video flickers?  The other hard drive likely doesnt have the correct drivers installed for your specific system. 

Using the original hard drive, does the problem return to flickering video? Or does it shut down now using using any AC adapter?  I would make sure that you have the same make of AC adapter but the system performs the same way regardless of AC adapter, and the problem follows the battery if you use it on another system then yeah it may be the battery.  If the battery is fine though and the AC adapter doesnt seem to make a difference, you are likely looking at something wrong with the system board integrated video.

TB