Assistance in fixing or diagnosing A Asus X55A

I have a Asus X55A that stops as soon as it's powered on.(no beeps).

-Seems to be a motherboard issue.

-Tested parts separately: cpu/ memory ram/ power adapter/changed cmos 3v battery .(all fine)

-If I power up X55A with no ram, gives no beeps, and fan spins.(same with no cpu).

-Did cmos clear with no results. Battery 3v bios change did not help.(i know laptops have bios issues so I made sure bios was cleared without any residual power in mb/ caps)

-I can only deduce, it may have a defective chip... may even be main VRM the culprit. NOT SURE HOW TO CHECK/identify this... assistance or option or additional testing procedures are welcomed. I have a multimeter if anyone knows what V should I look for on the laptop's motherboard.