Some motherboards/Bioses are picky about locking, the WD1600JB is a known troublemaker .... (wild guess on the model
)
From Xbohdm for dummies :
QUOTE
Final tips!
Some PC Bioses seems to enable the Freeze Lock command on unlocked drives on bootup. When freeze lock is set you cannot relock the drive. This is rare though and might be disabled in some bioses. On my PC the bios only sets Freeze Lock on the Primary Master channel. Putting the xbox HDD on Primary Slave enables me to lock the drive again. Otherwise switching to another PC can be a solution if you should run into this rare problem.
As for options being greyed out/unavaillable, it's probably because of a poorly burned image. Re-burn the image at the slowest speed possible. You might even wanna try a different brand media.
Good luck.