Question New build crashing

[inoculum]

This is a new build that i have had for a month. Current specs, 2x8gb corsair vengeance vgx ram, MSI Tomahawk b450 motherboard, AMD Ryzen 3 3200g processor, MSI radeon rx570 armor 8gb oc egidion graphics card, 650w corsair power supply, unknown brand ssd, seagate 2tb hdd. First off this is my first pc build and to be honest i have pretty much no idea about pc's. Initially it had a gigabyte motherboard with an i3 processor that I got from my younger brother. i was experiencing crashing issues with it after the cpu cooler failed and it cooked itself. Replaced the cpu and motherboard for what I currently have in it and the pc ran flawlessly for about 3 weeks. Suddenly for someunkown reason the pc has crashed to a grey screen 5 times in the last 2 days all within the first 5 minutes of starting a game of either apex or modern warfare. All temps are staying where they should be and all drivers are updated, help?

 

[wpgwpg]

When it crashes, does it give a message or an error code? Without that, problem determination will be more difficult.