Unhappy [Q] can somebody please help me to go back to stock?

At first, my english is not so good and i'm a noob with computers...sorry!

I will try to explain as good as i can what my situation is about,

I have a HTC One and have to go back to stock for warranty.

The problem is that i really don't know what to do because i bought the Phone that was allready root and the firmware Android Revolution HD.

here are some screenshots in my dropbox, but can't find the main firmware in fastboot because the field is empty

EDIT: can't upload screens because i am new here

What else can i do, there are many, many ways and they are all different, don't know what to choose or do.
I am searching last 2 weeks every day at least 4 hours but till now i didn't do anything haha.

Can someone please help me with a step by step tutorial, and if you need more info, tell me what you want and how to do it.


On my bootscreen (volume down + power) is the following information...

-Apr 12 2013, 12:10:45-1

On the computer in fastboot usb (fastboot getvar all)

it will not show me the main version when i type "fastboot getvar version-main" it is empty.

-vers.boorloader: 1.44.0000
-vers.baseband: 4A.14.3250.13
-product: M7_ul
-platform: HBOOT-8064
-modelid: PN0710000
-cidnum: HTC__E11
( there is some more info but i don't think it is important?)