possible psu issue

Hello everyone, A month ago I bought a prebuilt PC, all components brand new but built in the shop by the seller and sent to me. It came with Windows 11 demo version, and after 20 min of playing the first game I download from steam, PUBG, it just restart after a black screen and a glitchy...

Well, This "condition" started a while ago (maybe a year) but recently it started to be outrageous and unbearable. While playing R6 , it suddenly turns into a black screen and the sound james. From that point on, I have to press the power button and restart it, and than all goes back to normal...