Screen went black after 10 minutes of gameplay

I was playing a ranked game with a premade. It was around 10 minutes and my screen suddenly went black. My computer was not lagging and it had just been switched on. Nothing was open in the background. I had to close league completely and reopen. I was lucky my team got ahead but we would have lost if they had not. I got leavers after this (which i am not complaining about) but it was not a nice experience. A game i had played early had an AFK on the enemy team. His premade said he AFKed due to a black screen as well. This has never happened before. My game has been acting strangely recently which i can understand since it is preseason after all. I hope this issue does not affect other players in the future.