Xbox 360 banned from xbox live

[Thejld]

Ok so my buddy got this xbox from ebay that was rrod, thinking he could fix it and he couldnt. He didn't even attempt to so he gave it to me and i fixed it. It had been opened before and I fixed it and turned it on, has 8955 dash, and it is banned from Xbox live. I dont know why its banned though, but the possibility of it being flashed comes up to my mind. I dont have a computer at the moment so i cant really test if its flashed. anyone know how to tell if its flashed without putting a modded disc inside it? any help will be aprrecciated, thanks

[StoopidMunkee]

the only ways i know of is what you stated
plugging it to the computer
and putting a copied disc in it.