I've done some research on this and I haven't found any really good suggestions. Here's the summary:

• HP dv9000 laptop with Vista (updated regularly).

• No recent changes - was working fine

• Put it into hibernate mode

• Tried to restart it the next morning and it woudn't start. All the lights would come on, there was on brief flicker of the HDD light and then not too long after the machine would shut down and then almost immediately try to start again. It just keeps going through the same sequence until I shut it down. The screen stayed black.

• Tried all the easy stuff: tried disconnecting the power and took out the battery and let it sit for a while. This worked in the past when I had a similar problem but no luck this time. Tried alt-ctrl-del, F8, del, esc and every other Fn key but it won't break out of the situation it's in and go back to the boot sequence. I tried putting in the (Neosmart?) recovery boot disk and it seemed to read it but nothing different happened. I swapped the memory sticks but that didn't change anything.

I suspect that the hibernate file is probably corrupted. I'm thinking of getting a new disk drive and starting over (and then see if I can read the current drive as a second drive). It seems a little bit extreme but I don't see a better way out of this. I could send it to HP who will probably charge a fortune to do something similar.

Anyone have any better ideas on how I can force it to boot (or any other useful suggestions)?

Well, after a day of research and anxiety, I finally got it working again. The manual suggested holding down F10, F11 or F12 as the system is started. Thought that I'd tried that earlier but decided to try it again. F10 did nothing but F11 almost immediately brought up a screen that allowed me to drop the hibernation file and to proceed with a normal boot. After that, it was a normal startup.

Here's a further update.
I shut the system down normally last night and when I started it up this morning, it seemed to be in the same loop shutting itelf down and then restarting. Using F11 (HP Recovery Manager) took me to an HP Recovery screen that offers various options. I chose to do a chkdsk for the the main (Windows) partition. That ran for a long time and didn't find any errors. After that, the system booted up normally. There is probably still a problem and it will probably do the same thing at startup the next time so I'm not there yet.

Keep us posted please. If you hadn't given us post #2 you might have had a suggestion that the MBR could be corrupt - which it clearly isn't.

There is autility you can download called HD Tune (I use v2.55). That might provide useful diagnostics.

Just reset the computer. Common issue.

What does "reset the computer" mean? There are many different ways of doing this (with different effects) - so what specifically should chrishea do in your opinion?

In my opinion take out the battery. Usually gets rid of this issue.

Read post #1. He's done the battery thing.

load up the Device Manager from Control Panel. check to see that the TurboCache drivers are showing as installed (ie, no yellow triangle), as can cause all sorts of issues if they corrupt, such as BSOD on waking from either Sleep or Hibernation.

And before the bandwagoners hop on, it is an Intel caused issue.

Video and Audio drivers are also known culprits

Well I ended up back in the same situation where the machine would fail and reboot in a loop. Using F11 I was able to get into the HP Recovery Manager again (after a dozen or more unsuccessful attempts) but the best that I could do was to get into a command window where I could use xcopy to make copies of some of my files. I got pretty sick of that so I figured it was time for a more drastic solution. I bought a new hard drive (double the size and faster) and an external housing for the old drive that allows me to plug it in as a USB drive. I then went through a couple of days of experimenting and researching to figure out how to downgrade to XP and get all of the devices recognized. I just had enough of Vista (after about 2 1/2 yrs).

I spent most of the day today trying to find an XP video driver that would recognize the native size of the LCD screen and support that. The HP site provides a bunch of drivers for other devices but no video driver for my machine. I went through innumerable web sites that ranged from "it can't be done without a new video card" to ones with utilities to force the resolution that didn't work. Neither the HP or the NVidia web site were much of any help. Finally, many many hours later I found a site with a download for an NVidia driver (not the first such site but the others didn't work). I installed it and it worked. I'm not totally out of the woods yet but I think that this will work out ok. I have many hours of re-building to do but in the end i will be good. The difference in start up and shut down time and performance in general is pretty significant. That's partly the new drive but a lot of it is XP.