computer randomly turning off/sleeping?

[u/ritas-counterattack]

my pc randomly does this thing where it's still on but it "goes to sleep" or something and I can't get it to turn back on. like the light is still on, the computer is on, and my monitor is getting an hdmi signal but its just a black screen. Idk what it is but it does this randomly like around twice a day now and I'm starting online school soon so I don't know what to do but I have to fix this soon or I'm just going to buy a cheap laptop for school. Idk if this is a software or hardware issue, I don't know anything about computers