Modded 360 Issue in need of advice...
I have an older 360 that I modded about 6 months back, and has worked flawlessly up until recently.
To give a brief history of this machine, it originally had an error with it which caused for the sound but no video issue (no RROD). With reading this and that and a few other things, the best I could determine was to attempt the RROD fix, as some people had stated this helped their issue with Sound/No Video.
Well, after the fix (and already having another 360 console) I decided to flash the DVD with iXtreme. Having a Sammy25 if my memory serves me correct, and flashing with iXtreme 1.6, I was then in possession of a handy modded 360, next came getting burned backups to work.
Obtained Kreon drive for my PC, and began backing up. SUCCESS! (Little did I know that I had a HUGE case of noobitus, and was unaware of abgx360.. *slap on wrist*) But, no matter, my only desire was to play system linked, or games that were simply single player. I did not feel the need to risk getting on LIVE when I had a 360 that was perfectly capable of performing that task, RISK FREE.
Ok, so now here comes my current delima/question. I recently made a backup of my game Left 4 Dead 2. Once again having noobitus and being unaware of wave 4 disks that were out and needing the activation.iso file in order to have them play. Finally did my homework, researched a bit and found out the needed information that would lead me to getting the xbox back up and running with the game. YES! I had done it. Damn I was good............... Until about 10 minutes into the game.
For some reason my 360 will completely stop all audio/video output. TV goes to the no source screen and I am left with a

I have tried multiple games, but still same outcome...
Any thoughts/ideas would be greatly appreciated.. I hopefully put enough information above to allow you to be able to see what the 360 has gone through, and maybe I am just missing something simple.
Thanks