I have an HP Pavilion dv6810us laptop, and earlier today, I left my computer running while I left the room. When I came back, the monitor displayed only a black screen. I tried everything I could think of, but it wouldn't respond, so I forced it to shut down by holding down the power button.
Since then, when I try to boot it up, its lights briefly come on and I can hear the fans spinning and the DVD drive (or maybe the hard drive?) clicking, but it shuts itself down after just a couple seconds. Nothing ever appears on the screen. After a few more seconds, it boots back up and does the exact same thing. This cycle repeats itself until I hold the power button down for a long time to force it to stop.
-----------
My computer has also been having other strange problems for a couple months now. These include the following:
Windows (neither 7 nor Vista) won't recognize my DVD drive. The light on it won't come on, and the button doesn't open it. However, the DVD drive will open at the HP boot screen (I'm not sure of the technical name, but it's what used to appear when I first turned on my computer).
The computer performed its turn on/shut down cycle once before, but I left it alone for a few hours and it magically fixed itself.
Sometimes, my laptop doesn't recognize that it's connected to the AC adapter even though the blue ring surrounding the power input is lit. The blue light on the front left that indicates that the computer is charging does not come on, and Windows tells me I'm running on battery power. I have to jiggle the cord for quite a while to get it to work, and even a slight bump can sometimes cause it to stop charging again.
I have had multiple freezes where my screen turns slightly paler, and little columns of horizontal green lines are superimposed on my screen.
The laptop once said "OS not found" when I tried to boot.
After shutting down the computer, it often took me multiple attempts to get it to start again. It would usually freeze at a flat black screen or the HP startup screen a few times before I would finally get it to work.
-----------
I've googled a bit, but nothing I've tried has worked so far. Someone mentioned that hitting delete/escape/f10 while booting might help. Nothing happens when I press delete, and when I press esc or f10, the computer stays on and keeps whirring, but the screen never comes on and it never makes any noises. I have also tried removing the battery and holding down the power button, but this didn't work either.
It seems like whatever the problem is, it could be pretty serious, and unfortunately my warranty has run out (bought the computer in June 2008).
Any ideas for what I could try to fix it? Thanks!