OK, this is a repost of what happened to me, just a little more specific
I have a v1.0 xbox with a new power supply, a switchewd out from thomson to what is now a samsung dvd drive(but it is the xbox retail dvd drive, just not for this specific xbox), and i have now put in the original hard drive(that matches the mobo) back in. I have formatted it with slayers, but it is a 10GB seagate, so it made a 2GB F: Partition. i have cleared everything off of it and it is 100% stock. i then logged onto live, it did that update thingy that takes like...15 seconds(if that), and i thought oh shit, im banned....nope, i rebooted and i was still fine...
so everything is fine....then i wanna play foundation in halo 2, so i go to my other xbox and get the gamesave and put it on my memcard. I am pretty sure the save is PAL, but not hacked, and i started playin on live with it and it worked fine.
the next morningi got on agaion, and everything worked fine. then i tried hooking up a second controller to log in as guest, and it would not let my guest log on.....i then went to troubleshooter, and it gave me the modified hard/softyware error, and continues to every time i try to log on.
any ides?