This post exists thanks to a friend of mine, Alexandre. I have an old trusty Sony Vaio laptop (FZ11Z) which one day froze while reading a video then displayed green and purple lines. After a few reboots, that was permanent, happening from bios screen to Windows. A good way to find out what was going on is to go into Device Manager where it reports an error 43, which means that it disabled the device acceleration and reverted back to a plain VGA driver. This is how it looked like when faulty:

I was about to order a 200 euros motherboard to replace this since my diagnostic was busted GPU which is unfortunately soldered onto the motherboard. This is when Alex made me aware of a condition that affects most Sony laptops of that generation.

The fix is to get a heat gun, I got this one in Argos. You will need to take the cover and screws out to expose the back of the laptop. You will need to unscrew all the heat sinks around the CPU and the GPU to expose them. The NVIDIA GPU is the one on the right handside:

Make sure you cover everything around where you are going to blow hot air to avoid melting any other parts. I used 2 layers of cling film (alloy), like this:

Heat this with a heat gun for about 2mn at 300 degrees celsius. Point the gun downwards with a distance of at least 15cm, to avoid burning the chip, then let it cool down for at least 30mn.

This is it, fixed my laptop in no time, here is a video of a boot after the manipulation 🙂 Fixing a motherboard with a 26 euros tool versus ordering a new motherboard for 200 euros, feels good 🙂