Laptop Freezes after boot to desktop

[drjman]

I am working on a HP nw8240 laptop for a friend and am running into some weird issues.
After sitting for 30 minutes or so i can boot up into vista, but after it reaches the desktop after a minute or two, it freezes. I do a hard power down and try to start again and the bios post screen won't even come up. I have also tried a knoppix disk (in case it was a windows problem) and it fully booted up and after a couple minutes at the desktop it froze. Some times it will freeze at the windows loading bar while booting up.

I have replace the thermal paste on the CPU, graphics chip and the mobo chip. The fan works properly and all the dust from inside (there was very little) was removed. The hard drive remains very cool and passed quick and comprehensive tests (in bios). the memory passed all tests as well.

What is strange is this almost certainly looks like a heat problem, but i kept the keyboard off for a boot and everything remained ice cold. No sign of excess heat, much less minimal heat.

My guess would be a thermal sensor gone haywire, but I don't know where to go from here.

Any help is greatly appreciated.

{EDIT}:Steps Taken:
1. Reapplied thermal grease to CPU, GFX and southbridge
2. Ran knoppix, Vista (still froze)
3. Ran Hard drive tests and passed
4. Ran memtest and passed
5. removed all dust from inside laptop (not very much to remove, surprisingly)
6. tried to reinstall XP but froze during initial file copy (the part right after the quick format)

 

[mpilchfamily]

Well you pretty much rulled out heat. So its time to move on to checking the hardware. Run memtest and see how the RAM holds up.

 

[drjman]

Passed memtest no problem. Laptop was warm, but nothing unusual and for an hour of memtest it did not freeze. It's still running and i'm gonna leave it running overnight to make sure i can't get it to freeze. I also ran some hard drive tests and no problems there.

So far the only time i can get it to consistantly freeze is a couple minutes after booting to windows desktop. It did freeze on knoppix the same way, but after that i was able to have knoppix run for 45 minutes before i rebooted.

One thing i think i should elaborate on is that when it does freeze, i have to wait like 10 minutes before it will start up again. What happens is I will hard shut down the laptop and when i turn it back on it doesn't POST (no HP Rom based Setup splash screen). Once i wait a few minutes (like its cooling down, but it isn't hot) it works.

again, thanks for the help

 

[mpilchfamily]

Run CKDSK. Seams like the HDD may have some curruption on it. Once you get any damaged sectors repaired you should try the repair install again.

 

[drjman]

I have since formatted the hard drive. I don't know if that will affect running chkdsk from the XP boot cd recovery console but i will try it. "setup is loading files" as a type.

 

[mpilchfamily]

If it was a quick format then it hasn't fixed any bad or dieing sectors. So i suggest you do a full formate. Though it may be better to replace the drive next chance you get.

 

[drjman]

I decided to do some local tests on my desktops after pulling the drive out and it would randomly power down and start right back up. Any time there was a sustained load on it. So i went and bought a new drive put it in, installed xp fine, got into the desktop fine and blam. froze again. So it looks like it may not be the drive after all. There isn't anything left to replace that doesn't cost more than the laptop is worth. there aren't any real settings that can be changed in the bios and i did update the bios recently so i re flashed it and still the same problem.

 

[superunknown98]

I had the exact same problem with an old Compaq duron 800 laptop. The fan never seemed to turn on enough, and the laptop would get hot but not overly so. Then i found it had a bad HD, so i replaced that. A few months later it wouldn't even load past the windows loading screen. Probably has to do with a damaged drive controller or chipset. Who knows.