A while ago I took the back panel off of my laptop. (HP Compaq, 5 or 6 years old) I did this so I could clean it out as there was a lot of dust. I put everything back together, nothing was loose looked fine. I would push the button and the light would come on and I could faintly hear it boot up. Nothing would come up on the screen then after about 4-5 seconds it would turn off.
Not sure of the problem, maybe overheating, or not reading the HDD.
Thanks for the help in advance.