Hi,
I'm a software engineering student, and I had a similar problem yesterday.
I logged on, got modified xbox error, messed around and changed the dash, xbox-live updated the dash (didn't know banned xbox's could do this).
I have no idea how I'm banned, and i don't see how it could be from live games with the modchip on. I kind of suspect I got banned from corrupt/inconsistent EEPROM/x-live files on HDD. serves me right for messing around i guess
Anyway since the update the ban arror message changes to xbox-live is no longer found, with WXYZ
0000-000B
0000-F001
008A-0C62
AFFF-0018
I don't know what the codes were back when it said modified xbox.
edit: quoted too much