[Q] HTC Desire stuck on startup logo and cant enable debugging topic

Hey all,

First off I'm a bit of a n00b with all this stuff so please could you be as basic and precise as possible when answering the question? And take me step by step of whats needed to be done? Thanks :) Also I'm using a MacBook Pro.

HTC Desire 300 300s

The phone is stuck on the hts logo and won't pass it. nothing happens and won't startup or anything.
I need to unlock boot loader but cant do this because I cant enable debugging because the phone won't sync to any pc or even through HTC sync because the phone cant turn on.

This is what comes up when I turn on using down volume button

G3V PVT SHIP S-ON RH
HBOOT -1.16.0002
RADIO -14.10.36Q4.13
OS-1.04.841.3
eMC -boot

I read up about flashing in a custom ROM or something but apparently I cant do this since "S-ON". And it gets a bit complicated from there for me. Please could anyone explain very simply to me how to get out of this hole I'm in. Can't seem to do anything due to the phone being stuck on the startup h&c logo screen. Tried factory resort and deleted cache etc. Nothing seems to budge it.

Thanks for reading and if you have any help for me it would be extremely appreciated!!