There's a few things you can try but you left out details that I use to give a nod to this or that.
In most cases I can hook it up to something else or check the OSD works but details are too slim to call it PC or monitor.
Tell more and test this monitor on something else. I'd be more specific but the model number is missing.
Video with problem https://youtu.be/MXTcnb7Ru2s