Which Mac is this exactly? More information would be helpful for getting it going.
Display does not look good. Do you have an external display you can try? If the external is OK, then the problem is with the internal display or its connection. If the external looks the same, you may be looking at a logic board problem having to do with the graphics chip or its driver.
Do you have access to an Apple Store? They could provide an external display if you don't have one and run a comprehensive hardware test for you so that you know exactly what you are dealing with here.
With no OS installed, you might expect to see something like a flashing question mark or maybe something else. Here is a link to an article on startup screens:
About the screens you see when your Mac starts up - Apple Support
Try an external and see what happens with it.
Good luck!