to me it sounds like a softmod was installed on a chipped system..
any way regardless of the cause..
try to donwload hexen "heimdalls xbox enineering disk" burn it to dvd-r at 4x or slower and put that in the xbox. turn off the xbox then turn it back on..
Wait for it to load, the LED on front of the xbox should go red.. Just wait for it to finish..
when its loaded go to chipped/tsop tools and do a fresh install C partition..
password should be:
A Y B X
That should give you back your dash and leave your files on the hard disk in the other partitions.
-=Edit=-
why was this on top of the forum it says its an ancient post.. i didnt check the date till now, but how has it re surfaced so it shows on the 1st page?