Help HTC one M8 not starting up

[Android Question]

Hi, first time on here and struggling to find an answer - heres hoping.
recently my daughter ok'd an update on the phone, it was plugged into charge, as it was taking a bit of time she unplugged and took upstairs an plugged back in. An hour or so later phone buzzed and start up screen - white HTC displayed, but would not start up. i have tried all the pressing of buttons etc to 'reboot' (not sure if know the right terms here!) there is a small crack in the screen and therefore cant send it back to sort under warranty (the crack has not caused any problems for the last 6 months) i have managed to get a scren up by pressing vol + and power, this says in pink at the top ****locked**** in pink with lots of text below. i have tried factory reset, reboot and this has no change or effect. get the red traingle up then try again, and again.... i am willing to try anything. PC says devise is connected but wont do anything when i try to open, so i cant get inot the phone at all. is the phone bricked? can this be solved? i am not a techy person but i can follow instructions! any help would be very greatly appreciated

 

[EarlyMon]

If you have an SD card in your M8, power off, remove, power on. If no change, reverse and put the SD card back in.

If the phone lost power during one particular phase of the update, it could be in a world of hurt and unrecoverable.

But if not, you may be able to sort things out with a little help.

Please hold volume down while powering on to get to the screen you described with the pink lettering on top, provide everything you see, line by line, from there through the date. If you can get an OK picture of it (nothing fancy) linked instead, that's fine as well.

Need to know what carrier you're on.

Highly recommend that you register and join us, so I can move this thread to the M8 forum if necessary and still maintain contact with you.

I'm very probably going to have more questions, this Mini-SDK (sdk-tools.zip file) is going to be needed to get answers. -

http://androidforums.com/threads/adb-guide-updated-2014-11-11.443072/#post-5389081

Unzip, it'll create an sdk-tools folder.

I'll be back later to help and in the meantime, others may come along to help as well.

While waiting, charge the phone.

I'll be back.