Laptop Overheating. Help

[Th3Kaka]

So my laptop GPU Nvidia Gt540M was running normally ( about 50C when idle and 70C on intense tasks), but then, the motherboard broke and I had to replace with a new one, unfortunately, the motherboard that came wasn't the same one, before Nvidia GPU had 2GB Vram, and now 1GB Vram, also before motherboard was rev 1.0 and now is 2.0. So after I replace the motherboard, laptop GPU started overheating, now idle is around 60C and it can reach to 100+C in seconds in intensive tasks. I tried cleaning, thermal paste change, replacing fan. But it seems that problem is either motherboard or Nvidia GPU. Other components runs at normal temperatures. I really need your any kind of help. Thanks !

Specs:
GPU: Nvidia Gt 540M 1GB and
Intel HD 3000
CPU: I7-2670QM 2.2 GhZ
RAM: 8GB DDR 3 1333mhz
HDD: 500 GB
OS: Windows 10 Pro

 

[geofelt]

Likely, your cooler is not mounted well.
Using too much paste is bad.
Possibly the cooler is not secured properly or is not tightened down level.
Could the air intakes or exhaust be blocked?
Is the cooling fan running properly?

 

[Th3Kaka]

Likely, your cooler is not mounted well.
Using too much paste is bad.
Possibly the cooler is not secured properly or is not tightened down level.
Could the air intakes or exhaust be blocked?
Is the cooling fan running properly?

My cooler is mounted well, also there's not too much or too little thermal paste, there is no way for intakes to be blocked (Im only using my laptop on desk), and cooling fan is running properly, also he spins almost always, even when i'm not using any demanding tasks. This laptop had checked already twice at service, and cleaned with thermal paste change. Problem may be with motherboard. Do you have ant solutions?

 

[geofelt]

Desktop processors will show 10-15c. over ambient at idle even with a stock cooler.
Laptop processors are even more energy efficient so I wonder why you are seeing 50c at idle.
The problem must be related to the motherboard change.
Consider taking the laptop back to whoever did the replacement and repair.

 

[Th3Kaka]

Desktop processors will show 10-15c. over ambient at idle even with a stock cooler.
Laptop processors are even more energy efficient so I wonder why you are seeing 50c at idle.
The problem must be related to the motherboard change.
Consider taking the laptop back to whoever did the replacement and repair.

Well it had changed about 2 months ago, so i cant unfortunately take it to the service for redo. Any suggestions for fix without taking it to service ?