I have a laptop with a broken screen which I use televisions for as a monitor. I just got a larger TV second hand, and the computer will only display the boot-up process. The second it gets to the login screen, the display shuts down and goes back to displaying "No Signal". I know the HDMI cord works, as the old display works fine. There's only one HDMI port, so when I try to connect to the new TV, I can't see the display at all. Any fix suggestions?