HP Pavilion dv6445us laptop keeps power cycling without boot up

[shashgo]

I have windows vista on the computer.  Lately, about two days ago, I noticed that my computer doesnt boot up all the way.  When I press the power button, the LEDs light up, and I hear the fan.  About 5 seconds later, the laptop shuts down and then turns on  again, again with no proper boot up, at least I think there is no boot up, I cant see anything on the screen.

I have already tried taking out the battery and the ac cord, holding the power button for 30 seconds to dissipate any static and then just plugged in the power cord.  But same thing happens.  What should I try next

[Geek-9pm]

HP has excellent resources on their web site. Have you looked at the documents relating to your laptop and the symptoms?
http://www8.hp.com/us/en/support-drivers.html

[shashgo]

I did but I couldnt find anything helpful.  Theyve removed the chat option for hp computers.  Anyway, is it possible that maybe a loose connection on the LCD is causing the laptop to cycle on and off

[Geek-9pm]

The more common cause is total failure of the battery. The battery has a short and is sucks power from the AC power unit. Not very common, but it does happen. Can you use the laptop without the battery? The HP laptops can run on only AC power.