Did replacing a thermal pad with paste cause these unexpected reboots?

I have a 6 year old Toshiba laptop running Windows 7

A few years ago I took it apart and swapped the Pentium T2370 CPU for a Core2Duo T6400, which was absolutely fine.

And then maybe a year ago, I took the whole thing apart to clean out the fans, re-apply thermal paste, etc. While doing this, I noticed the GPU (GMA X3100) chip had some kind of blu-tac stuff instead of thermal paste, which I guess was a thermal pad. Anyway I removed it, and put thermal paste on there instead.

Around that time (but not straight after), I got a few random reboots. When booting up, it rebooted maybe once or twice before booting up and being stable.

However, that progressed and now it will reboot like 5-6 times at the Windows startup screen (with the Windows logo) and then I can log in, then after a little while it will crash, sometimes with weird display artifacts, and then it will reboot, and after a few more times it seems to be fully stable. If I stress test the GPU there are no problems.

But I also noticed some weird things with the SSD, like at one point I lost all of my Chrome profile data, and whenever I touched files/folders in the Chrome data folder, it would reboot/give me errors. If I tried to change the profile tab in Chrome, it would reboot.

At one point I had two video files on my desktop, Cast Away and the latest episode of The Apprentice

While trying to watch Cast Away, it rebooted every few minutes. When I watched The Apprentice, it was fully stable. Also I had 3 failed Chrome downloads on my desktop, and when I tried to delete them it said there was an error and wouldn't let me.

So this led me to believe it could be the SSD, and when I tried running CHKDSK (/f switch), it would get to random parts, and then reboot, and try again.. and reboot, and try again... and reboot, and try again

So today I took the SSD out (64GB Verbatim) and put it in an external enclose, and ran CHKDSK from my other laptop (/f /x switches) and it completed fully (only took about a minute to do the whole thing, is that normal?)

So I put the SSD back in my laptop and it rebooted after a few seconds.

I don't have a spare HDD to try, so can I be sure the SSD is OK? If I replace the paste with a thermal pad like before, should it be OK?

It's an old POS laptop, but I'd rather get it working if possible.

 

Yes, the thermal pad is to fill the gap between (what I think might be) a chipset and the actual heatsink. This requires a thermal pad and not a thermal paste, because the gap is too large for thermal paste to effectively transfer the heat.

I suggest you take a putty or something and measure the height (usually in 0.5mm increments) to decide what thickness of new thermal pad you should buy.

Arctic on amazon is pretty decent with 6w/mk.

 

Sometime a US Dime is the right size to sandwich between the heat sink and the processor. This is what I did for a HP DV6xxx laptop and this improved heat dissipation and no more sudden power off.

 

Careful with dimes and whatnot, you're effectively doubling the number of contact surfaces between the heatsink and the heat source.
i.e. Heat source <-> Dime <-> Heatsink, as opposed to Heatsource <-> Heatsink.
Moreover, coins tend to have non-smooth surfaces, so the possibility of getting small air bubbles is greater than just a simple metal shim.

But the advice is the same regardless, get Artic thermal pads on Amazon, they are dirt cheap.