go to supper 1 click on ur computer and hit unroot and superuser will go away

Flash a Stock ROM Paticular to your device

If you unlocked your boot loader, there is no way to relock it

If you want to make sure its unrooted, factory reset it.

Factory reset it m8

Factory Reset WILL NOT WORK. Goto XDA Developers And Find A Stock Rom. Because Once Phone Is Rooted....Theres NO Going BACK!

There are two methods of unrooting an HTC Desire.
Methods:
Get the latest RUU for your region from Shipped Roms. This is an exe file. You can run this file directly from PC. Then connect your device when so prompted.
The second method is to flash the rom.zip directly from the Android bootloader interface, after renaming the Rom.zip (which is actually obtained from the RUU) to PB99IMG.zip [See EddyOS's excellent step-by-step guide for dummies, in the FAQ below]
Method1 does not need any explanation (If necessary, I will add illustrations of this process later along with error codes)
Method2 is illustrated below.

Note: The following post illustrates the actual steps necessary to unroot your HTC Desire by running the PB99IMG.zip. This is also the method to upgrade the software with the RUU, the last method to fix bootloops cause by a bad boot, and also the way to unbrick an SLCD bricked Desire. Note that another simple method exists to unroot the device, and that is by directly running the exe file of the RUU from Windows. Though simple, this is slightly riskier, since complications with Windows drivers, or a sudden power surge or PC reboot can semibrick/brick your device. The following method using PB99IMG.zip eliminates those problems.

Unrooting is just one of the steps necessary to unbrick an SLCD bricked HTC Desire. The process is a pain for these users because they cant see anything on the screen and left pressing keys in sequence, whose function they can only guess. Also they need to wait specific amounts of time before pressing the sequences.

I'm making visible the steps which the Android system proceeds through, when you run a PB99IMG.zip to unroot your Android device. I've also included the time taken before each step while running the WWE 2.29 RUU as PB99IMG.zip. The time isnt much different for other ROMs. To be sure, just give it about 30secs more than the time I've noted.

Initial steps:
Create a goldcard if you want to convert a branded Desire to unbranded, or vice versa, or to make a Desire of one region (CID) accept software written for a phone of another region.
After creating the goldcard, format it as FAT32. If more than one partition exist, delete the rest, and format one as Primary and FAT32.
Put the file PB99IMG.zip into the root of the goldcard. Note that the name must be PB99IMG.zip and not PB99IMG.zip.zip. Windows has a tendency to rename it as the latter.
If you dont already have the PB99IMG.zip, you can get it by running the RUU, and while the RUU is loaded (dont start the RUU upgrade. Just click on the exe, and when the welcome screen of RUU shows up,) search in your Temp folder for the file rom.zip. Hint: To quickly navigate to Temp, Type the following into the Run window: %TEMP% [If you still get this step confused, see EddyOS's excellent tutorial on this, in the FAQ below]
To run the PB99IMG.zip, just reboot with Vol- and power button pressed.

I'm describing the whole boot process below for Reference, though.

Hboot mode (Vol- & Power key. Key them pressed for a 5-6 secs

FOR INSTALLING ANY RUU AS PB99IMG.ZIP

Press Vol- , then w/o releasing it, press Power button + Vol


After 3-4 secs, the following screen shows up momentarily:


Fastboot
Recovery
Clear Storage
Simlock
This shows the above few options for 2-3 seconds, and then directly checks for PB99IMG.ZIP. It displays:
SD Checking
Loading
PB99DIAG.ZIP
Pb99DIAG.nbh
PB99IMG.ZIP
When it finds PB99IMG.zip, it starts to load it (13 secs after you press the Vol- & power key)
It gives the next options after 2min 20seconds (for the WWE 2.29 RUU) from the initial key press of Vol- and Power key.
Parsing.[SD zip]
1. Bootloader
2. Radio V2
3. Radio_Cust
4. Boot
5. Recovery
6. System
7. Userdata
8. Splash1
9. Splash2

Do you want to update device?
<Vol Up> Yes
<Vol Down> No
So, net key sequences involved:
Back+Power
Power again
Vol Up
If we chose No, next option:
Do you want to reboot device?
<Vol Up> Yes
<Vol Down> No

If you pressed Yes, then:
Update is in progress..
Do not power off your device.
1. Bootloader -OK
2. Radio V2 -OK
3. Radio_Cust -OK
4. Boot -OK
5. Recovery-Unzipping/Updating
6. System
7. Userdata
8. Splash1
9. Splash2
It cycles through each of these in turn. For me, it took exactly 2 min 17 secs for time when I chose to apply update, to when update was completed.

(Note: At times, it may update the bootloader and reboot. If you have an SLCD screen, when the device reboots, you may not see anything onscreen (black). At this point, it is notable that the device boots to Fastboot instead of Bootloader, so you will need to press Power button again to get it to resume the update process. Once it completes, you will be presented the options to reboot the device. So you just need to Press Vol + after some time)

It displays:
Update complete
So you want to reboot device?
<Vol Up> Yes
<Vol Down> No

Congratulations. Your phone is now officially unrooted.
On rebooting, HTC screen shows up for a few seconds.
Then a green Down arrow in a green circle shows up for another 5-6 seconds.
Then, HTC screen again.
Finally, HTC screen disappears and the HTC Quietly brilliant logo shows.
Your device now boots into the Android phone.
Total time taken: 6min 30 seconds.

If the Rom is incompatible with your SLCD device, at the reboot stage, you will hear the momentary vibration. Then after about 10-20secs, you will hear the HTC Quietly Brilliant tone. The phone will boot, and the keys light up after about a min, indicating that the Android system has booted up. Since the Rom is incompatible, there's still nothing on screen. To shutdown the booted up phone, press power key, then swipe your finger vertically up-down like you do to unlock your phone normally, which is exactly what you're doing. Then keep Power button pressed until the phone vibrates. This means it is presenting you with the Power menu. At this point press the trackball once, then once more. The phone will now shutdown. At this point you can flash your SLCD compatible update.zip (OTA) and unbrick it.


FASTBOOT mode

Back+Power key:
4 options:
Bootloader (For running PB99IMG.zip)->Choose with Power key (This loads the Bootloader/Hboot mode)
Reboot
Reboot bootloader
Power down

Bootloader (Hboot mode) or PB99IMG update mode.

Performs the following check on the PB99IMG.zip:
1. Bootloader
2. Radio V2
3. Radio_Cust
4. Boot
5. Recovery
6. System
7. Userdata
8. Splash1
9. Splash2
Do you want to start update?
Vol Up: Yes
Vol Down: No
So, net key sequences involved:
Back+Power
Power again
Vol Up

If we chose No, next option:

Do you want to reboot device?
<Vol Up> Yes
<Vol Down> No



No brings up the following options:


Fastboot
Recovery
Clear Storage
Simlock