mobile

Hi,
I have been using Cyanogenmod, pretty much since I got my phone. I am tired of the non-working stuff and bugs in it and want to go back to stock, but I have no idea how to go about it. I used the CM auto installer method and I have no backup of my original system. TBH I want to flash ViperOne now, but they require the latest firmware, but mine is very old (I think it was 1.x). I have really no idea where to start and how to go about upgrading the firmware. I was not able to get S-Off :(.
About 2 weeks ago I downloaded a RUU package from a site looking like an official HTC one, but have no idea what can be the damages of running it. It is just a 1.5G .exe.

My questions are:

1. What will happen if the RUU is not for my CID and MID?


2. If I just run this RUU, is there any chance to brick my phone (I am still S-On)?


3. Will this update my firmware version?


4. If the process is successful, will I be able to flash ViperOne without S-Off then?

I also found this thread - http://forum.xda-developers.com/show....php?t=2428276, but have no idea what to download. My phone is unlocked from Hong Kong, but I am using it in Europe (if that information is even necessary).

Any help and pointers are welcome.
Thank you!