360's connected via HDMI are known to do this. HDMI input seems to reset itself every time you switch. Don't think there's a solution for this, except for avoiding switching inputs...
I found a fix. First, i found a thread on another forum that tells you to cut a looped wire in the cable and switch it to TV not HDTV, but i didn't have that loop in mine!
After struggling to get the cable back together, I got some tape and covered the two pins that this loop is meant to be connected to.
The thing is, it reset itself when it was installing a game to its HDD. Hopefully it hasnt caused any damage...
LOL thanks. I sorted it out in my post below lol. If anyone comes across this, PM me and I'll share the info. I'm on my iPod atm and it's not the easiest way to post.