Frequent BSODs and black screens, also IRQL-NOT-LESS-OR-EQUAL

For the past month or so, my computer has been getting frequent Blue Screens, the most common error is IRQL-NOT-LESS-OR-EQUAL. I also have random black screens that shut down my computer while playing games (mainly Minecraft, to be specific) and while watching YouTube videos. There have also been some problems with my internet browser. When I click the icon on the taskbar, it will load and then...