Question : Why  wont a hp laptop power up?

I have a hp pavillion 9000 laptop that wont power up.  I went and got a different power adapter, I have changed memory, took out the battery and then used the new power adapter and even was able to take out the motherbd battery but there is now power.  The only light that comes on is the power button light when you push it and then it goes off when you let go.  It soulnds like a motherbd but not sure

Answer : Why  wont a hp laptop power up?

North America call 1-866-671-7362 from 6:00 am to 11:00 pm MST, 7 days a week.