A family friend had that issue with the 17 inch HP from the dv6000 and dv9000 series. HP shipped a box and they had it corrected inside the week.
Some insist on a fix short of letting HP fix it. So here it is -> They put in another motherboard.
On approx 4 out of 5 occasions my laptop will not start-up. When this happens I manually shut it down by holding down the power button, wait for 20 seconds or so then start again when it starts fine.
I like to have my CPU as idle as possible so keep processes to a minimum and diligently manage all start-up programs.
I use Norton's 360 and regularly wipe all temp files and scan for Registry issues with 'CCleaner' and update all programs regularly.
-HP Compaq Presario A900 Notebook
-Vista Home Premium - Service Pack 1
Thank you for your time.