im reaching 90c+ temps while playing dota2. do i need to clean my laptop and put a new thermal paste in? its voltage is also reduced to -135mv offset and fans are 100%

Is there a tutorial on how to disassemble my G752? I am in doubt that I can disassemble this myself, or if not careful I may forgot where to put the screws and some things that can be removed. TIA

The problem I noticed while I am gaming for about 4-5 hours, my laptop overheats on about 85C-90C. i checked the right fan, which is for the GPU *I think* is blowing air, it also just peaks to 65C-74C. Then I checked the left fan which is for the CPU...