HP Pavilion wont boot – failing cpu?

Hi!
This one is killing me.
I have an hp pavilion dv6t -2000 laptop. When I power it on, the lights turn on and fans spin. Nothing on the screen. Occasionally it WILL boot into Windows and will run for a while, but will always freeze at different points.
I have replaced the motherboard and identical symptoms happen. I have replaced the hard drive. I have replaced the RAM. I have drained the cmos taking out the battery. I removed the WiFi card and DVD drive. Same symptoms after all of this.
I think the last part is the CPU – an Intel i7 720qm.
when it does boot I can get to the bios and even that freezes if I’m in there too long. Men test does the same thing – runs to 80% or so then freezes.
Thought?
Thanks!
Dan
Answer #1
you checked the cooling fan and it’s good ?
Answer #2
Have you tried re-seating the heatsink with fresh thermal paste ? (I tend to stick with Arctic MX-4)
Clean both the heatsink and cpu with Isopropanolol and a soft cloth carefully to remove any old paste. You can buy a half litre of Isopropanolol in any chemist for about £2. It also comes in useful for cleaning stubborn stains around the house.
*Edit – if it’s got a thermal pad on already, you can remove it with acetone (nail polish remover) quite easily. Both methods just stay clear of the cpu pins.
Answer #3
The fan looks good – turns on and throttles up and down.
I reseated the heatsink when I replaced the mobo – it SHOULD be ok…
Answer #4
when you can get into windows, have you check the error log (event viewer) for clues ?
Answer #5
Hmmm, no, i haven’t actually but mainly because I didn’t think it was a software issue. I’ll take a peak if I can get in. Thanks