Compaq Presario CQ40 Blinking LED

Compaq Presario CQ40 come in several model which is I divided into to chipset class which is Intel and ATI. Model with Intel chipset did not having much problem since I start servicing this model but ATI is in contrast. The most common problem is for ATI chipset model is POWERED ON with NO POST but with CAPS/NUM Lock blinking.

Before you do any servicing or taking your CQ40 apart, do visit the HP page on details about CQ40 blinking code -- link at bottom of this page. Here is the list of the blinking code (taken from HP.com). I suggest you do hard reset and re-seat RAM module. On two occasions, on two units of this model, I just re-seat RAM module, and it works fine. So, sometime, 4x blinking not actually cause by graphic controller problem.
 
Blinking Code Translation Table

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

For more details, please visit this page.