Yesterday I was on my computer, its an HP Pavilion dv9308nr Notebook PC, when it suddenly put itself to sleep. Or at least the monitor went black. I did what I usually do to bring it back up, which is shake the mouse and if that fails, quickly push the power button. Well, the mouse was dead, the little optical light was off, and the power button didn't do anything, it just sat there. So I did what I would usually do if I couldn't get it to restart which is use the power button. Now it's been doing this sleep thing pretty often lately and it always comes back on after I restart it, but this time nothing happened. The lights on the keyboard came on, but the screen stayed black. The fans didn't even start up. It would stay this way for about 30 seconds and then restart again, and it just does this over and over again until I turn it off. Nothing pops up on the screen its just black. It won't boot at all.
I had a suggestion thinking that it was overheating, but I had it sitting at this point so it was getting plenty of ventilation, so I'm not sure what to think. If anyone could give me some help I would really appreciate it.

Also, I started it up this morning and the fan will go on for a couple of seconds, then go off and they cycle will continue as before.

Thank you

Still could be heat related, Check that all the fans are spinning and that the heat sink is on tight, Just had a customer that one of the CPU heat sink mounts broke and was causing the CPU to over heat in about 3-5 minutes due to lack of contact. Also, air movement is nothing if its full of dust inside.

Sorry, just saw that it was a laptop. So you can't really open it up.

But again it could be the fan or dust clogging it.

When you first turn on the laptop, they usually spin the fans up. See if you notice that or if the fan turns on at all before it turns off. If they do, then you want to check for dust, you can get some caned air or if you know someone with an air compressor, you can spray the vents and see what comes out. It could still be the Heat sink itself is loose, but you would need to take it to a shop, unless you feel you can take it apart (not recommended for the novice).

Other then that only thing I can think of is maybe a loose power jack, causing the laptop to switch to battery and thus draining the battery.

Hope this helps

I have the same laptop and the same thing happened to me. I only had my laptop for a year and a half.

I took it to the geek squad and they told me it is probably the video unit. I forget the exact term. A computer expert friend of mine also thought it was the same thing.

I was told it was not worth fixing... so I bought a new laptop! I did not buy an hp!

Im thinking OTS is on the right track, Heat problay broke something down, from what you have described it souds like a Bios Chip( because your not getting any boot up), I don't think that it's a power issue because it is powering up and running.

I would rule out the video card because it keeps restarting, but then again really it could be anything, since laptops are so compact,

Im thinking you should take it to your closest shop they'll be able to tell you for sure :)