My PC first started having trouble while gaming: the monitor would suddenly go black, although it stayed powered on instead of showing a no-signal message. The problem later began happening during simple tasks, then even shortly after startup. Now the monitor reports that no cable is connected, while the computer's fans and lights still turn on normally. I initially suspected the PSU, but before buying a replacement I'd like to know whether the symptoms point more toward another component.
2 Answers
A failing PSU seems less likely based on these symptoms. Power-supply problems more commonly cause shutdowns, failed starts, freezes, or the need to hard-reset the computer. Since the PC stays powered on, try isolating the display path first by testing another cable and monitor, then check the graphics card. If multiple known-good cables and monitors behave the same way, the graphics card is a strong suspect and may need to be replaced.
The graphics card may be failing, especially since the issue began during gaming and gradually became more frequent. Reseat the card and its power connectors, check whether the fans spin normally, and test the system with integrated graphics if your processor supports it. If the display works through integrated graphics, that would point strongly to the dedicated GPU rather than the PSU.
I already tested three different cables and two separate monitors, so those don’t seem to be the cause.