My PC was exposed to rain through the top vents, and I've already had to replace roughly 80–90% of the components. Despite that, games still cause the system to crash to a black screen, restart, and sometimes end in a blue-screen error. The computer also occasionally powers itself on at random times, including during the night. I've ordered a replacement power supply, but I'd like to know whether these are typical signs of a failing PSU or if the water damage could have caused another underlying problem.
3 Answers
The random power-ons are concerning after liquid exposure and could indicate a short, corrosion, or damage around the motherboard’s power-switch circuitry. Disconnect the machine from power while inspecting it, and don’t keep testing it if there is visible residue, moisture, burning, or corrosion. Replacing the PSU is reasonable, but if the crashes continue afterward, test the RAM, graphics card, motherboard, and storage separately and review the crash dumps.
Blue screens aren’t automatically proof of a bad PSU. A failing power supply can cause them, but it’s relatively uncommon because the voltage usually has to be unstable without dropping far enough to force an immediate shutdown. Since the system is producing BSODs, check the Windows minidump files and analyze several crash logs. They may point to a faulty driver, memory problem, graphics card, motherboard, or another component damaged by the rain.
A PSU can definitely shut the computer down when the system is under heavy load, which often shows up when launching demanding games. A black screen followed by a restart after several minutes of 4K gaming could fit that pattern. However, because the PC suffered liquid damage, don’t assume the PSU is the only problem. Make sure the replacement is a reputable model with enough capacity, and avoid continuing to use the damaged unit if there’s any possibility of moisture or corrosion.

That sounds similar to what I’m seeing: games run for around ten minutes, then the screen goes black and the computer restarts before eventually showing a blue-screen error.