When start up my xbox the screen stays blank were

try a different input on your TV or replace the AV cables

it might bea problem with your actual video cord that plugs into the tv.... umm my xbox has a lot of issues too but ive never had this. id suggest you let it say off for a while and try somebody elses cords that connect the xbox to the tv to see if its an issue with your xbox or if its with your cords. ill also suggest you call microsoft and they can troubleshoot...

please rate my solution :) thanks

Since your sound works, you know the xbox is booting properly.  Check two things: 1) try another television to make sure it's not the tv.  2) try another cable(from a friend?) to see if the cable is bad.
**Also, if the video settings were saved on an unsupported setting, it could cause the screen to not show video.  If you try these 2 things and you think someone might have saved bad settings, I recall a button combination you can use to reset certain things, and I try to help if it comes to that.

your graphics processor IC chip needs its solder joints reflowing, and the heatsink re securing.

This will solve the problem.

Regards

FixMyConsole

already solved it. thanks. i couldn't see the xbox settings blade because of the blank screen so switched my component cable to the tv setting instead of the hdtv setting, then i could see the dashboard in non-hd and switched the resolution to 720p while simultaneously switching the component cable back to the hdtv setting. that worked.

Check the status of the "HD" switch on the side of the video connector, nearest to the Xbox. I have the same non-HDMI Xbox. If I have it hooked up via component to a non-HD TV, and the switch is on "HD", it will show no video.

Probably you turned hdtv on change it back to tv

It sound like E74 Hana chip error very common, you could try fix it yourself, there are tutorials on the internet to fix the problem but you'll have to open your xbox and that would void the warranty.
the xbox sometimes doesn't show the red lights because the chip is not totally fried, so with the proper handle you could fix it.
If you do want to fix it by yourself here is a link showing how to do that.
http://forums.xbox-scene.com/index.php?showtopic=646900

Hope it helps

I do not see any reference on this problem and I even checked with Sony. If you are on a cable box, I suspect that is the problem.

just call 1800-4my-xbox