well, try inserting a cd with only hacked bios burned on it. If that does not work, download ozxFlash from
this site. You load that up, after a while it will open the dvd tray automatically and ask for a bios cd. Put a disk with only bios burned to it (renamed to "bios.bin"). Don't hit the eject button, the tray will close automatically after 2 mins. Then it will flash the bios and power off your xbox automatically. The chip should then be flashed and working.
and make sure your using the correct size bios.