Hdmi Crap

Hello, sup so I have a dynex 32 Inch tand my computer worked fine yesterday, but then when I came home I tried connecting it didn't work, so I used my brothers computer it connected fine to the tv so I knew it wasn't the HDMI. Then I did FN and F1 and I put duplicate nothing showed up, I restarted my computer; nothing and I even tried it on a different tv and it didn't worked Do you think it's my computer? Why and How do I fix this?