I have a custom made computer I know nearly nothing about (a friend built it for me to use). I'm trying to attach a second monitor (a Roku TV) so I can record videos better but I cannot attach the TV as well as the other monitor (LG brand) or the other way around. Either only one of the two HDMI ports I have is not working properly or something I can't even begin to understand is at work here. I know little about what my computer is made of but I can try to figure it out if you need the information.

This setup runs on Windows 10 and has ALWAYS run on Windows 10. When I try to "Detect" the second screen--be it the Roku TV or the original monitor--it always says it cannot detect the second monitor. I'm not sure if I need to install driver updates or if the second HDMI port is even functional.

Any help would be much appreciated.