Take the battery out and disco from the wall. Press and hold the power button for 60 seconds! Put it all back together and try again. IF no go, try below!
OK< well since you have already opened the case, TAKE THE RAM BACK out and try to boot again. Does it do anything different this time (it should if it is missing RAM)? If it doesn't do anything different, the POST failed (hardware failure), and more than likely it is the Motherboard (that is where POST is run).