Frequent PC Crashes While Gaming

[RSBH]

Guys I need some help....
My PC is experiencing a lot of crashes while gaming, example FIFA 17 will just freeze mid game after playing 4 or 5 games(approx 30 mins to an hour), 
as soon as the game freezes i can see my CPU temps go crazy 80 -90 degree C (the LEDs on the Motherboard tell the temps). At the time of writing this the last crash went to 99 degree C.
this happens for other games also, like battlefield 1, watch dogs 2 etc.
I have tried turning down the graphics but doesnt help much.

My Specs:
Intel i7 6700K runnig at Stock
MSI Gaming M5 Z170A Motherboard
16 gigs DDR4 3200Mhz ram 8x2
GTX 970 MSI
256gig kingston SSD
2TB WD HDD
CoolerMaster Seidon 120V Liquid Cooler
Cooler Master 750 watt PSU

My drivers are upto date, i feel i shoud reapply thermal paste and see if it helps but wanted to get a second opinion.
If there is anything im missing please let me know, any help will be greatly appreciated.

[astrosheen]

16 minutes ago, RSBH said:

Guys I need some help....
My PC is experiencing a lot of crashes while gaming, example FIFA 17 will just freeze mid game after playing 4 or 5 games(approx 30 mins to an hour), 
as soon as the game freezes i can see my CPU temps go crazy 80 -90 degree C (the LEDs on the Motherboard tell the temps). At the time of writing this the last crash went to 99 degree C.
this happens for other games also, like battlefield 1, watch dogs 2 etc.
I have tried turning down the graphics but doesnt help much.

My Specs:
Intel i7 6700K runnig at Stock
MSI Gaming M5 Z170A Motherboard
16 gigs DDR4 3200Mhz ram 8x2
GTX 970 MSI
256gig kingston SSD
2TB WD HDD
CoolerMaster Seidon 120V Liquid Cooler
Cooler Master 750 watt PSU

My drivers are upto date, i feel i shoud reapply thermal paste and see if it helps but wanted to get a second opinion.
If there is anything im missing please let me know, any help will be greatly appreciated.

 

Remounting the cpu cooler is where i would start, those temps are really high.