My monitor randomly stops detecting my computer, then cycles through the available input sources instead of staying on DisplayPort. I replaced the monitor, but the problem continued. HDMI had previously stopped working too, although it seemed to work temporarily when I tested it again. Could this be caused by a loose connection, a failing graphics card, or another problem with the computer's video outputs?
2 Answers
A failing graphics card is one possibility, but check the simple things first: reconnect the cables, inspect the ports for damage or looseness, and try a known-good cable. If the monitor loses signal across multiple inputs and cables, testing with another graphics card or integrated graphics would help confirm whether the card is failing.
Since the issue happens with more than one monitor, the problem is probably somewhere in the computer’s video output path rather than the display itself. Try another cable, firmly reseat both ends, and test every available output. If HDMI and DisplayPort both fail intermittently, the graphics card or its drivers could be the culprit. A dock or adapter with another video connection may also help narrow it down.

HDMI had failed before, so I switched to DisplayPort. It started working again briefly when I tested it, but the same signal loss eventually happened there too.