When I take out the battery and put it back in and connect the power supply the light will go on but no boot up no fan no nothing just the light will come on and when I push the power button the light will go off and no boot up the battery is fine I check it with the multimeter please help me

You checked the power output of the AC adapter? (Charger)
VERY close to 18.5 Volts? (DC)

Okay.
What is the condition of the DC Power Jack?
(Port on the laptop that the plug of the AC adapter, plugs into. May be marked on laptop as DC IN )

The DC Power Jack has a Center Pin, and an outer metal shell.
AC adapter removed, Battery removed, see if you can take a small wooden object, and gently wiggle the Center Pin.

Does it move?
Try to move the cylindrical metal outer shell.

ANY perceptible movement means the DC Power Jack is bad, OR, the solder joints on the motherboard for the jack, may be cracked.

Laptop needs to be disassembled, (FOLLOW Anti-Static Precautions), and the DC Power Jack checked out.

A) Cracked solder joints just may need to be re-soldered. Depends on the extent of the damage.

B) A damaged DC Power Jack means replacement of the jack.
Excellent de-soldering, and soldering skills are required.

Post the Product Number of the laptop. It's on the bottom of the laptop in a white Service Tag.
P/N = Product Number

{Note*
DO NOT post the Serial Number on a public forum. S/N }

Regards,
joecoolvette