u/that1p2

i was trading and all of a sudden i saw this pop up on my screen around 10 hours ago and whenever i try to trade it keeps saying the same thing

https://preview.redd.it/twi7epllac2h1.png?width=1189&format=png&auto=webp&s=1ef35cb7b90fc7f65f2a594cb8f2f588f1df989e

so whenever im not a game my pc will shut down whenever I am browsing the internet or doing normal stuff like go on discord this happens every 45 minutes to an hour it is very frustrating and i don't know what the problem is like it will stay on but the monitor will just be black and i cant turn it back on