XBOX Live update wont update error message

I have tried everything to get my son's XBOX 360S 4GB to take the updates that the XBOX state need to be performed to no avail. I spoken with XBOX on 2 separate occassions to try and correct the error message and still no help. The call center people were a waste of my time. The error code I keep getting is:

Can't process the update. If problem persists, go to XBOX Support

Status Code: 3F4B-4099-1780-0700-C000-000E

I have downloaded the update onto a DVD and tried to install the update that way and nothing as well as to a jump drive. None of the recommendations on XBOX or any of the forums have helped. My son will bring his external hard drive home from his grand parents home (that does have the update) and it works fine. I have removed his external hard drive we have at home to try to get the update and nothing, Xbox wants to charge me $80 to send in for repair or replacement (refurbished). Is there anything else I can try or replace on my own? This is the 2 time since we have had the XBOX that it needs repaired. My son doesn't do the updates when they pop up like he should and I wonder if that has caused his system to not respond to the things we have tried to do to fix it. Please help!