RAISINSCOOKE This sounds like the kind of issue that someone needs to help you with in person. If you don't have a friend or family member who knows how to troubleshoot computer issues, see whether there's a local PC repair shop that would perform diagnostics for free or a low price. It's very possible that one component of the computer is fried while everything else is fine, and if you have a standard desktop, that one component could be replaced.
Without knowing your specs, I can't really offer anything concrete. However, if the PC has a dedicated graphics card, you could try removing it (just the GPU, nothing else) and plugging your monitor into the motherboard. If it works, that makes it clear that the GPU or its power delivery is the issue.
If you don't know how to remove a graphics card, there are plenty of YouTube tutorials. Look for one about upgrading a GPU, since that will show you how to remove the old one.