Monitor's not displaying anything!

So, I’m running into a whole string of headaches with my PC. First off, getting Microsoft OS installed was an absolute struggle; first, it claimed a file was missing, then after finally getting halfway through my programs and following a restart prompt... nothing. The machine seems to be running, but there's zero activity, and the CLR/CMOS light on my ASRock motherboard is staying lit. I’ve dealt with this before—I managed a temporary fix by pulling the CMOS battery from the board to reset everything to its last known state, which got me back up and running once. But now? The OS is reporting missing files, making it impossible to install my graphics driver. To make matters worse, after a power cycle, I've hit a new wall: no video output at all. The tower sounds like it's humming along just fine, and I initially thought maybe my old Samsung CRT—which is honestly a top-tier classic—had finally given up the ghost. However, I tested it with an LCD monitor belonging to my roommate, and that shows "no signal" too.
If anyone has any bright ideas, I’d really appreciate the help.

1. It’s looking pretty likely that your graphics card is acting up,
2. What’s the exact error message popping up on macOS? (that detail makes a huge difference)
3. Could you list out your full system specs from top to bottom?