Default htc one hang on htc logo plz help

hello friends
i got a htc one it hangs on htc logo the customer siad it happen suddnly
i try to unlock boot loader from htc site all thing gose ok but the bootlodar is still lock
this is the info
M7_U PVTSHIP S-ON RH
HBOOT-1.55.0000
RADIO-4A.20.3263.16
OpenDSP-v32.120.274.0909
OS-3.25.599.2
eMMC-boot 2048MB
Oct 9 2013, 17:55:59.0