monitor randomly goes black for a second then comes back

check the monitor's menu for an auto input or auto source setting and set the input manually. with auto on, some monitors rescan their inputs when the signal flickers for a moment, and you get exactly that one-second blackout. same if you go through a dock or an adapter, test straight into the PC once.

Swap the cable before anything else. A loose or cheap HDMI/DisplayPort cable drops the signal for a second exactly like that, and it's the cheapest fix. If it still happens: - turn off FreeSync/G-Sync/variable refresh, both in the monitor menu and the graphics settings - drop the refresh rate one step to see if it stops - update the graphics driver If the screen also flickers when you nudge the desk, it's the connector. If it lines up with a game or video starting, it's more likely the driver crashing and recovering.