How can I tell if a problem is with my PC's graphics card or my monitor?

Bombchu

I have an Acer Nitro VG240Y pbiip, and up until recently I've been using a DisplayPort cable on it. The other day, DisplayPort stopped working. I ordered a new cable and I got it in the mail today, tried it out, and the problem was still there. The problem is that DisplayPort isn't working.
When I plug the DP cable in, I hear a Windows notification telling me I inserted a device. Once I switch to DP, I get a black screen and nothing else. Soon after, the auto-source switches to HDMI. I've tried turning off auto-source, plugging the DP cable into another port on my graphics card, and I've tried turning the DP Format to 1.1 and 1.2.

billsey

Well, there are three pieces to it, the GPU card/port, the cable and the monitor/port. You've got the easy one handled by trying a different cable so now we have to figure out how best to test the other two. Do you have access to another monitor with DP? Do you have access to another system with DP? You can also verify the display on the monitor is working by seeing the splash screen at startup and the OSD menu afterwards. If neither of those do anything it's more likely the monitor than your computer.