Hi, A short but effective guide for people who want to root their Sensation. This is what I did with my phone but it took me a lot of time to figure things out, so I'm writing this for myself and other people.

) First of all set up ADB and Fastboot. [GUIDE] Easy and simple adb and fastboot setup for newbies (Windows only)

To have working adb and fastboot system wide for basic commands just follow the steps below:

1. To get the HTC USB Drivers download and install HTC Sync (If you do not need the Sync application itself you can uninstall it but the drivers will remain on your system). 
2. temporary disable your antivirus software during the installation of HTC Sync. 
3. Download the zip archive 
4. Extract the archive on your C: drive. You will have C:\android-tools folder
5. Adding to the System Path globally to use the command without browsing to the containing folder
6. Go to Start and in the Search box type cmd, right click and Run as Administrator

copy or Type

                             setx path /m "%PATH%;C:\android-tools"

              TO CHECK IS IT WORKING PROPERLY OPEN COMMAND PROMPT (START -> SEARCH -> TYPE CMD -> ENTER) AND TYPE ADB IF EVERYTHING IS CONFIGURED PROPERLY THIS SHOULD LIST YOU THE ANDROID DEBUG BRIDGE VERSION AND THE AVAILABLE COMMANDS.

*HINT*: To use adb or fastboot with files in the Command prompt you have to navigate to the folder containing the file first (using the cd command) e.g. "D:\Downloads\Android" and then to execute the command.

Example:
Start -> type cmd in the Search box, then Enter. You will see
C:\Users\with blinking cursor
If your file is on another drive like the example type "d:" (without the quotes), or other drive letter to go to the relevant drive. Skip this if the file is on C: drive. Then type:
cd D:\Downloads\Android to go to the "D:\Downloads\Android" folder. If your path contains spaces (intervals) type it in quotes.
The command "cd.." brings you one folder back

Also download the ROM you wish to install on your HTC Sensation and put it on your microSD card. For 

this tutorial I choose ViperS v2.0   rom by team Venom

2) You have to unlock your bootloader first via HTCdev so that you can install EXT4 recovery and custom roms. In the dropdown list select ''All other supported models'' and follow the instructions.

If you successfully finished the HTCdev unlock tutorial, your phone has a unlocked bootloader.


3) We're going to install EXT4 recovery. But first download ''4EXT_Recovery'' or from drop box link "recovery.img" copy the recovery.img file to the folder where you installed fastboot and adb. If you followed the tutorial in step 1 the folder will be ''C:\android-tools''

Now make sure Fast Boot is turned off on your phone. Go to ''Settings > Power > Fast Boot'' to turn it off. Unplug your phone from your computer, it's time to turn of your phone and boot into your bootloader.

Press Volume Down Button and Power Button at the same time to boot into recovery. Now connect your phone to your computer and select fastboot.

(Power button to select, Volume Down/Up to navigate)

Go to start->run-> type cmd and press enter. A command prompt will now appear.

Type:

Quote:

cd c:\android-tools [press enter] fastboot flash recovery recovery.img [press enter]

EXT4 recovery is now installed on your phone. Turn off your phone in bootloader menu.

4) Open the rom (.zip file) you downloaded in step 1 and put the ''boot.img'' file in ''C:\android-tools''

If you followed this tutorial correctly, you already copied your desired rom your onto your MicroSD card.

Now we boot into the bootloader again, this time we select recovery.

First go to tools and enable "4EXT SMART FLASH"

Go to: wipe | format>and select: wipe data/factory reset (this may take a while), then select wipe cache and wipe dalvik cache.

Go back to main menu in EXT4 recovery and select ''install from sdcard'' select ''ViperSv2.0.zip''.

 After it's successfully installed, turn of your phone and just boot normally. It may take a while for your phone to boot up.

Your phone is unlocked,rooted and has a custom ROM.

Enjoy