Desire 300 s off

my desire 300 wit hang on logo flashing failed log here pls give information anf steps to clear thanks

Starting flash process…
target rom version: 1.10.401.4
found large-zip header, file count: 6
processing file 1/6…
sending ‘zip’ (25341 KB)…
OKAY [ 2.953s]
writing ‘zip’…
(bootloader) adopting the signature contained in this image…
(bootloader) signature checking…
(bootloader) rom parsing start …
(bootloader) rom parsing finish …
(bootloader) zip header checking…
(bootloader) zip info parsing…
Error: If your phone is S-ON and bootloader is UNLOCKED you cannot flash this image. You should make S-OFF or lock/relock your bootloader
FAILED (remote: 99 unknown fail)
finished. total time: 10.828s
Flash process completed.
Flash not successfull, reboot will not be done