Laptop Overheating Problems

[SneakyLunatic69]

Hi, recently I've ran into problems with my laptop overheating and I'm currently trying to figure out what could be causing the problem.

-I've already bought compressed air and cleaned out the fan and heat-sink. Both seem to be working well because I can feel lots of airflow and when I unplug the laptop and let it cool down it does so very quickly.
-I've also ran a full scan of my PC with Kaspersky Antivirus Free, nothing found. While I can't fully rule out the possibility of a virus, I do doubt it as the computer runs fine other than being hotter than the sun...
-I also already have a cooling pad and it does help a little (5-10C depending on what I'm doing), but I can't take it to university with me as it's just too big and I have enough things to bring!
-I also only use my laptop on hard desks to ensure it has lots of space and good airflow.
-I've changed all my power settings to try and save energy while plugged in and on battery.

Something I've noticed is that when plugged in, the temperatures increase by a good 15-20C regardless of what I'm doing.
Anyways, here's my current temperatures doing various things:

-Idle/Youtube/etc. Around 55-60C without the extra power fan on (50ish with it on)
-Playing light games such as Terraria or League of Legends: 70-75 without fan/ 65 with
-Playing heavier games such as Nier Automata or Just Cause 3 it's hit 80C+ and the fan doesn't seem to be able to keep up with whatever is producing the heat.

Once I exit the games the laptop does cool down quite quickly leading me to believe it isn't the fan or heat-sink at fault..
Also, when I unplug my laptop the temperatures drop almost instantaneously by 5-10C.

I've made sure all my drivers were up to date and I've ran CCleaner and a disk check recently. I haven't BSOD'd due to heat issues (yet...)

Tomorrow I'm going to try my friends charger (has the same laptop, no heat issues for him) to see if it's possibly an issue with that since the temps seem to be fairly normal when it isn't plugged in.

Specs:
OS: Windows 10
Manufacturer: Certified Data (London Drugs brand)
CPU: Intel Core i7-4710MQ CPU @ 2.50 GHz
RAM: 8GB
GPU: NVIDIA GeForce GTX 960M
Hard Drive: 1TB

Any advice would be greatly appreciated! Thanks!!

 

[th3p00r]

you mentioned clean the heat sink, did you put on new thermal paste?

 

[SneakyLunatic69]

you mentioned clean the heat sink, did you put on new thermal paste?

No I haven't taken it out to thoroughly clean it, just cleaned as much dust out of the components I could by just taking off the bottom of the laptop. I plan on doing it eventually, but I don't trust myself to do it alone without someone who actually knows what they're doing with me.

I'll try and get that done hopefully sometime this week if I have the free time to do so, or plan on it next weekend. Any other ideas of what it could potentially be if this doesn't fix it?