if by flashed you mean chipped, copied etc then yes but i wouldn't advise it as if you play a copied game online they can ban your xbox for ever :O shocking i know and people who mod there gamerscore...
I'm not sure what you mean... XBOX Live computer disc.....? I know for setting up xbox live, all you have to do is purchase a points card from some place like Gamestop, and enter the code when you...
If its a wireless, then u should have a little plug in to the controller,same with wired ones and there should be a button or slide button on the headset to turn it on then turn it on and boom there...