Display won't turn on after replacing motherboard (Please Help!)

[gizmo j]

I have a Asus X551CA and a while ago it would not start at all so I replaced the motherboard and now the laptop starts up.

I made sure the new motherboard has the exact same model number and CPU.

But the problem is the display will not turn on!

I tried connection the laptop to a desktop monitor through VGA and HDMI but it still will not show on the desktop!

Do I have to re-install windows or something?

 

[SBMfromLA]

When you turn it on... does it at least reach the BIOS screen? Is there anything that shows during boot? Does the HDD activity light blink?

 

[gizmo j]

When you turn it on... does it at least reach the BIOS screen? Is there anything that shows during boot? Does the HDD activity light blink?

The screen does not start what so ever.

However the laptop itself starts such as lights, fans, hardrive etc.

 

[ffg7]

remove main battery, disconnect power adapter from laptop, hold down the power button for a 20 count, re-install main battery, reconnect power adapter & turn on the laptop.