I have been documenting my laptop problem in the Vista forum (ref) but it seems that maybe the problem belongs here. The system is almost dead even though there is a way I can break out of it.

In a nutshell, there is something wrong at the POST stage that causes the machine to cycle on and off. I seems to do one quick read of the drive and then just sits there with the lights on and the screen black. After 20-30 sec it powers itself down and then immediately powers up again. It won't boot off a CD when it is going through its power on - power off cycle. Even though it starts to read the CD, the system powers down before it gets too far.

After enough tries, I can interrupt the loop with the Del key at which point it goes to the HP screen and then boots into windows. Once I'm able to get it started this way, it runs fine (I'm on it now).

Without going into the whole saga, I was able to create an XP system on a new hard disk (on this same laptop) and initiallty it was ok but it eventually had the same startup problem as the Vista system.

I already recreated the boot record just in case it was responsible for the problem. At an earlier point I also swapped out the memory sticks and used another pair (which didn't change anything). The fan is working. I haven't reset the CMOS (yet). I couldn't get the plug out and I was afraid that I would damage it or the mobo if I pulled on it too hard.

Any suggestions as to I can determine what is causing the startup problem?

Right - for all of you out there with HP issues around the DV6000 and I also think the 9000 range is affected.

The issue is beyond your control!!!!!!!!!!!!!!!!!!!!!!!!!

The situation is generally due to a faulty NVidia chip which HP is well aware of and there is currently a "Class Action" being persued in the "states" regarding this issue.

You still need to ring HP Technical Services on this issue EVEN IF YOUR WARRANTY HAS EXPIRED.

Certain machines within these ranges have had extended manufacturers warranties applied so even after your normal 1 year warranty or even your extended warranty (if purchased) has expired you COULD still have cover

Possible SHORT TERM solutions have included - taking off the battery, disconnecting from the mains and pressing the power button for anything upto 1 minute - to "discharge the capacitors" within the machine.

Oh and resetting the BIOS.

These solutions have ONLY worked in the very short term from my experience.

The machine requires a NEW MOTHERBOARD - DO NOT PAY FOR IT OUT OF YOUR OWN POCKET - HP need to sort it!!

I hope this helps you all out, we have had 4 machines successfuly repaired and 2 refused - so give it a go

The motherboard was replaced once before the warranty expired. At that time I think it was because the wireless interface died. I will give them a call and see what they say. I think there is a 24 month limit (from original purchase) but I'll give it a try.

The link to the HP "Warranty Service Enhancement" is:
http://h10025.www1.hp.com/ewfrf/wc/d...name=c01087277

Check the CMOS battery also- sometimes when the motherboard is replaced, they give you one off the shelf that's been sitting- or a recycled on that battery was the original.

I had pretty good luck this DV6000/DV9000 issue fixed 3/3 this week. repairing the nVidia controller issue. But it is not something the average computer shop can do.

Here is the latest update.

I left the system running for about a week. All the power saving options were turned off so overnight, it ran with the screen saver on. This morning, the screen-saver crashed and left me with a blank screen except for the Windows bar at the bottom. Finally time to re-boot.

I shut the system down and then I pushed the power button to turn it on. It booted normally. The only mitigating factor that I can think of is that everything was still hot so if there is a connection problem on the motherboard, maybe it is only a problem when everything has cooled down.

I've had the machine running continuously (under Vista) for a month or so. It booted a few times after Windows updates and that worked OK. I tried some restarts and I shut is down and then started it with the power button. That all worked fine. Swapped drives and booted under XP and that was OK too. If the problem is related to a connection problem with the NVidia chip, then I'll probably find out when I shut it down and let it cool off. That's my next step.

I am marking this as Solved even though I don't fully understand why it did what it did. Since I also posted in the Windows forum (since it wasn't clear if it was software or hardware) I put the closing summary there .

There may be a hardware factor in this problem but it still isn't quite clear. When I couldn't get out of hibernate and had to force a re-boot, it would appear that something was then detected in the Post process that wouldn't let it complete. Since the system is now booting correctly (from a normal boot), it would appear that the problem was created by Hibernate or there is some extra checking after a forced shutdown that detected some sort of error (which does not inhibit normal operation and isn't checked on a normal boot). This is all speculation. If anyone understands the details of what Post is doing it would be interesting to get a real understanding. Since Hibernate and Sleep seemed to trigger the sequence, I have them turned off and I'll do without them.

A bit of additional info.

I don't know if this was the original problem or not. When I fired up the machine this AM, it seemed to go into the same Post loop I had originally. I tried the (XP) Windows CD and when I tried the repair option it told me it couldn't find a hard disk. I could hear the hard disk turn but maybe something wasn't connecting right. I took out the disk, fiddled with the adaptor and then put it back in. The machine then booted up normally. Was this the problem all along? Don't know but if I get the same symptoms again, reseating the hard drive will be my first action.