Okay, I don't know if anyone has actually posted a guide to this, but my friend was having the "Invalid format" error on his Westinghouse HDTV.

Apparently this is caused when the Xbox TV settings are different than the TV/AV Cable setting ("HD" selector on the A/V cable). Our solution wasn't the simple "move the selector switch on the cable" one, so here's a guide for how we did it:

1) Make sure your cables are plugged into the COMPONENT input
(Yp/Pb/Br)on your HDTV.
2) Make sure your A/V cable selector is on "TV" mode (NO THIS WON'T
MESS UP YOUR TV, SO DON'T WORRY)
3) Turn on your Xbox and boot to the Dashboard, then go to the Display
Setting tab (Where you can change the TV Output from 480-720-1080)
4) Change from the current setting to the setting that is most
applicable for your TV (Our Westinghouse was 720p)
5) You should get the "If you would like to keep these settings, choose
'Yes'" popup. DO NOT CHOOSE EITHER OF THEM YET!!!
6) It tells you that if you would like to play in HD to move your A/V
switch on the cables to the 'HDTV' setting. DO THIS NOW!
7) Your TV will probably go blank..don't panic! While the TV is blank,
hit the "A" button (Choosing the "Keep these settings" option)

There you go! If done correctly, your screen should now re-appear in HD. If not, reboot your TV and Xbox.


**NOTE: This problem was fixed on a Westinghouse 27" HDTV with output at 720p. We also fixed this on my 1080i projector. I ASSUME it will work with any other HDTV.**

Hope this helps anyone with this problem...I know we were about to chuck our 'box out the window when I figured it out...


-Joe