I recently had a friend of mine install a 400gb hard drive and a new Xecuter 3 chip as well as a new DVD drive and it was working fine for about a month but now when I turn my xbox on the screen shakes. I can still load XBMC and I can get into games but its shaking very bad so you can't actually play. What could possibly be wrong now? Also is there anyplace you can safely send a modded xbox with many games to be repaired.

go into the settings and go to the flicer filter, try different filters, although it usually wouldnt shake that much. What video cable are you using? and how is it hooked up.

Have you switched the video mode by accident?

Make sure it's not PAL,
for all of us now,
NTSC is probably where you are,
so do that and answer (this will help, by far.)

How can you tell what region he is in?
Is it the way he types?

I don't think I have changed anything. I am using the original cables that came with the xbox. I played it late one night and when I turned in on the next evening it was just shaking. I cannot see clear enough to search through files or settings. I have also noticed that the color is now in black and white.

You somehow have changed to PAL settings. Download the Engima Video Switcher disc and boot that thing up and switch back to NTSC.

Thank you very much everyone for your help. I hate to ask but does anyone have a link where I could safely download engima video switcher DVD?

its on xbins. (check the guide in my sig)