Hey guys, I need a little help. My grandparents bought my cousin a xbox 360 for his birthday. It was used. It worked for about an hour and now when you turn it on you can hear sound but no picture. They have already bought a new cable and that didn't fix it. Any ideas? Oh, and it doesn't have the red ring of death, the lights are still green. Thanks for the help in advance.
try a different type of cable (composite, component, or hdmi)
also, if you are using the composite/component cable there is a little switch on the housing part that plugs into the 360 that switches it between HDTV and SD (HDTV is for component hookup, SD is for the composite). make sure that switch is on the correct setting or you won't get a picture.
Mine did the same thing. Would work for a couple minutes then the screen would go green/blue then no picture at all. MS said it was the graphics gpu that was bad but it was just overheating. Took it apart, used some new Silver Arctic thermal compound on the GPU and CPU and replaced the X clamps for the heatsinks with some nuts and bolts and now it works fine. Google X-clamp mod for the 360's if you wanna fix it for $10 and dont order those kits, you can get the same thing at home depot and frys for less.
May sound stupid, but make sure your TV is set to the correct input.
I was going to say the same thing after some more time to think about the issue. When I first hooked up my PS3 I bought used it would only show a black screen because my TV was not set up to the output from the PS3.
Contact MS and see if it is still under warranty. If so that is your best option, if not I can do the x clamp fix for you. You can come by my office and I will do it with you if you want. It may not fix it, but it is worth a try if you cant get MS to help.