Got a PC in the house doing something weird...
One of the two monitors goes into standby, comes back, goes into standby, comes back... after a few times the whole PC shuts down. Already reseated everything. Not sure if this sounds more like a video card failing or a power supply issue. Any thoughts/ideas?
without knowing the specs of the machine, that behavior sounds like a power supply issue, probably needs a much stronger one.
Usually running multi-monitor at very high resolution and then also gaming on it will increase the GPU load (and power draw) significantly and if the machine can't handle it you can get this kind of behavior.
Also there could be case/dirt/airflow issues if you havent changed anything in the hardware setup and this recently started happening.
It going into standby/shutdown can be the system shutting itself down due to overheating.