My PC randomly restarts playing Dota 2

[Rihari-Richard]

Processor: AMD FX(tm)-6300 six core
Graphics Card: AMD Radeon R9 200 Series, ASUS DirectCU ll
Motherboard: Gigabyte
CPU: Intel
PSU: Sea-Sonic Model: SS-750AM, 240V, 750Watts
8.00GB RAM
OS: 64 bit Windows 10

Temp reading can shoot from 23*C to 75*C within 5mins of playing Dota 2, but the PC will be fine playing movies for multiple hours.

The PC used to run fine and then suddenly the PC would freeze on Dota2 with the only solution being a restart, I completely factory reset the PC where it ran ok for a few games until this continued issue where the PC would restart itself 5-10minutes into playing a game of Dota2 with no error message on windows start up as in it was just a normal start up.

The PC has been running fine under non intense uses for hours besides recently this week where it has frozen randomly with a buzzing sound with the only solution being a restart once again, but that issue seems to be a recent and random sound issue compared to the continued restart issue with high intense games that always happens 5-10mins into a game.

 

[clutchc]

While 75C is a bit warm for the FX-6300, it is safe as long as it isn't a continuous 75C. But even that temp shouldn't cause a shut down by itself. I suspect something else, probably the PSU.
What PSU (make/model)?
What gfx card?

 

[Rihari-Richard]

The Graphics Card is an AMD Radeon R9 200 series, I'll open the computer to find out the power supply unit.

Edit: Ok PSU: Sea-Sonic Model: SS-750AM, M12 ll 750Bronze, 250V, 750 Watts.

 

[clutchc]

The Graphics Card is an AMD Radeon R9 200 series, I'll open the computer to find out the power supply unit.

Edit: Ok PSU: Sea-Sonic Model: SS-750AM, M12 ll 750Bronze, 250V, 750 Watts.

That is a good PSU and its size is more than enough to handle any of the R9-200 series cards. But it would be nice to know which 200 series you have.
R9-270
R9-270X
R9-280
R9-280X
R9-285
R9-290
R9-290X
R9-295
Run GPU-Z and it will tell you: https://www.techpowerup.com/gpuz/

Next, I'd eliminate most possible software conflicts by 1) running CCleaner and doing the Clean and Rgistry portions both: https://www.piriform.com/ccleaner/download
And 2) begin eliminating as much stuff as possible that starts with Windows. Any apps that can be run manually on an as-need basis rather than having them load automatically when the OS loads.