How do you figure out if it's the video card or the monitor thats is not working?

i see no light inside the monitor and no heat coming out but the tech from my internet provider said it was the video card and i don't wanna buy a new monitor if it's not the problem, the monitor is 3 years old.|||If you know the monitor does not turn on, that's most likey the problem, your Internet provider is just that, they deal with the Internet, not a pc technician, replace your monitor, you'll be good to go.|||Try getting your hands on another monitor just to test.|||I like the idea of getting another monitor to test and see if it works but many monitors have a self test that they do when they start up. If your monitor is ok but the power switch is not working then that would be the thing to fix. It's important to make sure everything is plugged in and turned on. I would think the Device Manager for Windows would indicate a problem if the video card wasn't working properly. Right click on My Computer and select properties and form there you can get to Device Manager.