Solving The Problem
1. First, duct-tape all the external vents on the unit, so no air gets in or out.
2. Turn on computer, let the boot sequence go for about 5 seconds (wait until the fan speed changes from fast to slow during the boot time) when the LED on the quick play lights for a second time and the fan speed is fast press ESC button or F10 or CTRL+ALT+DEL.
3. Plug in the AC power adapter then wrap the laptop in towels or a blanket for about 40 minutes or an hour.
4. Remove the blanket/towels and any other obstacle(s) on the vents, turn it off and let the laptop cool for about 20-30 minutes.
5. After cooling turn it on and hopefully the power will be stable this time round with no ON and OFF problem.
Basis of the problem
The common problem with DV6000 series is the video chip being over heated and detached a bit from the mobo.
HP had extended the warranty on a lot of these machines from 1 year to 2 years due to threats of lawsuits, because of this video chip issue. It is common with a few other models besides the DV6000, where they used the same GPU chip design (ATI)