my xbox has got green vertical lines

Try a different HDMI cable, followed by a component cable to see if it is the cable.

If the problem persists, you will need to send the Xbox for repair.

you need to make sure the xbox is not inclosed and has alot room around it. you may also need a new cable attaching to the tv as that may be damaged and if that deosnt work go onto the xbox website and file for a repair on the support page

I actually just got these vertical lines when I was playing a couple days ago. SO I decided to restart my xbox to make them go away, and when I turned it back on I got the E74 error code. I looked up how to fix it and some people suggested trying a spare
AV cable to see if that fixed the problem, but it didn't work for me. I now have to send it back for repairs.

Hopefully your problem isn't as severe.

I am having the same problem. I returned it for repair and of course there was no repair done becuase they said it was ok. They probably didn't put a game in it to see what was going on. The lines happen all the time. It starts out clear but than eventually
the lines appear and then gets worse and worse. I noticed last night that the XBox was really hot so I placed it on a cookie cooling rack which unfortunately that did not fix it. It is not tv, tried it on a different tv. I think my friend tried different
cables and it didn't work but I'm not sure. Please keep me posted on a solution if you find one.

ok if any one has a E74 error and the xbox is in a open area and you have tried it on a different tv and dose the same thing you have to send it in (the lines on the tv being displayed on the screen was saying that your xbox was dieing it did not have the
error yet sorry no ad-fence )

hope that helps