My laptop had been shutting down abruptly recently while I'm gaming so I decided to clean the fan and replace the thermal paste. I've disassembled it before to clear the dust in the fan and surrounding areas but this is the first time I took off the heatsink to replace the thermal paste.
I saw that the thermal paste on the cpu had hardened so I cleaned it up. I also cleared the paste (or was it a thermal pad?) on the gpu and removed the pads on chip A and area B. (I've no idea what those are.) Thereafter I used a cleaning solution to clean the cpu, gpu, chip A and the copper contact areas on the heatsink. After drying, I squeezed some thermal paste on the cpu and gpu and replaced the heatsink. Following an advice I read online, I took off the heatsink again to observe the area to check if there was good contact with the heatsink. It was slightly messy and some of the paste went over to the sides and some paste was over area C. I didn’t think it was a problem so I let it be. Also I didn’t put any paste on chip A or area B since they are in contact with the aluminium part of the heatsink rather than the copper parts. It seems that the pads are there previously as there is a gap between them and the heatsink.
After assembling everything, I tried switching on the laptop but the screen remains blank. I turned over the laptop to check if the fan is running and I saw the screen went gray for a moment but it turned black again. The fan was running though. I tried pressing the capslock button but the light didn’t turn on. Basically the laptop was irresponsive. I couldn’t even turn it off by holding the power button and had to take the battery out.
Thinking that perhaps the problem is me putting on too much paste, I disassembled everything and cleaned things up. Then I applied fresh paste over the cpu and gpu and ensured I didn’t put too much. After checking for good contact using the above mentioned method and looking from the sides after screwing the heatsink, I assembled everything and tried switching on the laptop again.
The result is quite similar to the one I mentioned above. I noted however that a few times the harddisk light (beside the power button) lighted up just for a moment when I powered on the laptop. Also now I can power off the laptop by holding the power button. However I still can’t get the laptop to run.
Do you know what should I do? Any ideas what chip A and area B are? Should I place a pad/copper shim over the gpu instead? Do I really need to put pads over chip A and area B?