HDMI not working dual boot

Hi, i just made a dual boot and one of my two monitors isn't working on linux (it works on Windows). I read many similar threads and can't solve the problem. Xrandr doesn't show HDMI output at all. It doesn't matter which monitor I plug to HDMI they don't work. I would put the output I get, but not sure how to paste it. Thank you very much in advance!