Can't figure out what's wrong with my laptop.

So a few months ago I took my laptop apart to clean the fan out, and while doing so re-applied paste to CPU. I also noticed some blu tac stuff on the GPU (thermal pad) which I messed up, so I removed it and re-applied thermal paste.

But when I booted it up, it rebooted like twice during bootup, then worked. However, over time it got worse. First 3-4 boot up attempts, then 5-6

Then it started rebooting after getting into Windows. Now it's really bad, and takes 7-8 attempts to get into Windows, then while using Windows it reboots. Sometimes it's every few minutes, sometimes I can watch a full film before it reboots. And if it doesn't reboot, it's weird artifacting on the screen (lines of colour, shaking, flashing lights, etc. and a buzzing sound if I was playing audio. Sometimes it just freezes.

I did a memtest on the RAM which passed, I did a stress test on the CPU and GPU which both passed. While doing chkdsk, the laptop reboots, but I took the drive out, put it in an enclosure and did chkdsk from my other laptop, where it passed.

Now, the weird thing is, when I boot it into safe mode, it works fine. So appears to be some software issue. I can move files about, install/uninstall programs, etc. So I uninstalled all of the drivers I installed (video, audio and wlan) and reinstalled them. But as soon as I attempt to boot into normal windows, it keeps rebooting like before.

Also, when I untick options in msconfig, or disable "automatically reboot on system failure" it doesn't remember the option. So I thought maybe the SSD IS to blame, even though it passed chkdsk, and maybe it set some areas with Windows files to read only which is causing problems?

But today I decided to wipe it and reinstall Windows. However, it boots the disc, says "Loading files" and then when it gets to the end, it gets to the "Starting Windows" screen and, of course, reboots.

I really don't want to buy a new SSD if the laptop itself is broken, I'll just buy a new cheap laptop.

Does anyone have any more ideas?

Thanks

 

Can you supply the manufacturer, model and specs of your laptop?

 

Toshiba L300-12H

but I replaced the CPU with a T6400 (long before this all happened), 2x1GB PC2-6400, Verbatim SSD

I mean I got the laptop in like 2009, so it is old, but I'd rather fix it than have to get another, as it works fine as an alternate/backup laptop.

 

Did you make sure your connections were all tight and fit correctly? It almost sounds like a bad drive? I replaced thermal paste on old laptop without problems. Are you sure you didn't miss something in the assembly process to cause this?

 

Nope, I'd taken it apart plenty of times before, and have also done so since (to check everything is good and re-apply paste, and now a thermal pad on the GPU)

So, before I was in normal Windows mode, and reading that thread about de-lidding a CPU, and every time I tried to watch the Linus video someone posted, it crashed after 10-15 seconds, but right now I'm in safe mode (enabled audio drivers) and I've been watching videos for hours, with no crashes or anything.

So it seems like driver issues/software. But if that was the case, why wouldn't I be able to re-install Windows?

 

Since you tried to reinstall Windows and the installation is failing, I'd think the problem is hardware related. It seems like you were reporting seeing artifacts in your first post so it could be the video card which should be integrated into the motherboard on that model.

What I would do first:
- Make sure you are on the latest BIOS for your laptop
- Re-seat the CPU and the RAM again and make sure the DIMM contacts are clean.
- Clear the CMOS
- Download a free Linux distribution like Ubuntu or Mint, and run it in Live mode without installing the OS. You can do this with or without the SSD installed and see how it responds.

If problems persist even in Linux, it could be a number of things including the motherboard or power supply. With such an old laptop, a failing motherboard is a possibility.

 

I thought it was hardware, but why does safe mode work perfectly?

 

OK, so my laptop was working perfectly in safe mode. Today I tried reinstalling Windows, and when it gets to "copying files" it crashes/reboots. So now I have an empty SSD...

Tried another working HDD, same thing.

Downloading a Linux ISO right now.

 

Safe Mode disables some hardware devices so that could be the reason why it works.

Looks like you eliminated the SSD as the culprit. You may also want to unplug the optical drive and wireless adapter as well and see how that goes.

Another thing to try is a power drain. Usually this is done by removing the power adapter and battery pack, and holding down the power button for around 20 seconds. This is designed to flush the motherboard's capacitors of any left over stored power. This trick has helped me in the past on my Dell laptops when some strange things started happening.

Unfortunately with hardware issues, since most is integrated into the motherboad, it is harder to diagnose a problem piece of hardware.

 

OK so from Googling it appears to be an issue with a capictor that regulates CPU power.

So my basic understanding is that the CPU is low on power (throttling) then when it needs more power, the capacitor doesn't have enough stored so it reboots. In safe mode Intel SpeedStep is disabled so not a problem.

And changing the CPU governing in Linux to "powersave" seems to confirm this as it's much more stable.

 

Okay, so in yet another turn of unusual events, today I opened up my laptop and took the T6400 out, and put the original T2370 back in, and now I was able to boot the laptop, install Windows and then run it with no reboots at all.

So could the CPU have been faulty even though it passed a stress test? Or is it because the T2370 is using less power than the T6400?

And if it still is a bad capacitor, is it because of this

T2370 VID Voltage Range
1.075V-1.175V

T6400 VID Voltage Range
1.000V-1.250V