When attempting to boot Ubuntu/Xubuntu/etc from a LiveCD, my screen displays "color scrambled" random pixels for a few seconds after the loading screen with the 5 dots, and then turns completely black with a few scattered red pixels. The OS continues to load and operate, but the red pixels continue to be displayed. They occasionally move around and flicker, a few trailing the mouse, but never dissipate. At first I thought it was just a quirk with booting from the CD, but after installing it alongside Windows 7 it still always boots with these red pixels. I've never had this occur before on Windows 7, so I'm sort of at a loss on what the issue is. Any advice on fixing the problem or providing more info would be much appreciated.
Most likely the HDMI cable going from your computer is bad and or has oxygen inside the cabling. If replacing the cable dose not fix the problem the HDMI ports could be dirty and or damaged.