This guide is for Windows users who don’t feel comfortable with Method #1.  It’s still really quite easy to follow as you’ll see…
Whilst these instructions will work, I’ll try to go into a bit more detail tomorrow and hopefully get a video tutorial up too.

Disclaimer: I take no responsibility for anything that may go wrong by you following these instructions.  Proceed at your own risk!

What You’ll Need

  1. unrEVOked3 for Windows – download

Preparation

  1. Uninstall HTC Sync if you have it installed
  2. Install the hboot driver using these instructions (it says Evo, but works for Desire) – when complete restart your phone
  3. Reinstall HTC Sync
  4. Double-click the reflash-bundle.exe file you just downloaded
  5. It will ask you where to install it, so just pick a location on your computer you can remember

Rooting

  1. Go to where you installed Unrevoked
  2. On your Desire go to Settings > Applications > Development and make sure you have USB Debugging turned on
  3. Connect your phone to computer via USB
  4. Run reflash
  5. Wait a couple of minutes whilst your phone is rooted
  6. If all goes well you’ll have a rooted phone

Final Word

Once rooted, you can install HTC Sync again.

At the end of this guide your phone should be rooted and you’ll be in recovery mode.  At this point you can restart your phone and continue using it normally, but with the bonus of having root permissions.
You’ll be able to run apps that need root permissions like ShootMe for screenshots, and Titanium Backup which lets you make a backup of all your apps and the app data (really suggest you do this if you’re going to install a custom ROM)

You can now move on to installing custom ROMS including the leaked version of Froyo if you like 🙂

UPDATES

  1. 17 July 2010 09:29: Added “Reinstall HTC Sync” step.  This will make sure the phone is always recognised and prevent it from being reported as “disconnected”.  Still need to uninstall so that you can install the hboot driver without interruptions.
  2. 21 July 2010 19:18: Added note that phone should be restarted after installing hboot drivers

Here’s a clearer guide on how exactly to setup the ADB drivers on Windows, with screenshots for each step.

  1. Follow the installation section of this post.  Ignore step 8 (“Windows: install the latest Android phone drivers using the instructions”)
  2. Browse to the android-sdk-windows folder:
    Windows SDK Folder
  3. Run SDK Setup:
    SDK Setup
  4. Close the Refresh Sources box (pictured above) if it opens.
  5. Close the Choose Packages to Install box if that’s open too.
  6. Click the Settings option on the right
  7. Under Misc, check the box which says: “Force https://… sources to be fetched using http://…”
  8. Go on Available Packages and click the + (plus) sign next to the long URL (http://dl-ssl.google.com/android…) to expand it
    Available Packages
  9. Select Usb Driver package and press Install Selected
  10. Select Accept under the terms and then press Install
    Install USB Driver Package
  11. When the installation is completed, close the Installing Archives window
  12. IMPORTANT: In your SDK folder you’ll now have a new folder called usb_driver.  This is the location to search in the rest of the tutorial when you’re required to locate the driver
    USB Driver Folder
  13. Make sure you have Device Debugging enabled on your phone by going to Settings > Applications > Development > USB Debugging and ticking the checkbox.
  14. Connect your phone via the USB cable.  You’ll notice the Debugging icon in the notification bar, and opening the notification bar will show “USB debugging connected”
    Debugging Notification
  15. If you’re on Windows XP, follow the steps described in the Perform A Fresh Installation section here
    If you’re on Windows Vista or Windows 7, follow the steps described in the Perform A Fresh Installation section here
    REMEMBER: Where it says “Click “Browse…” and locate the folder where you copied the installation package.” it’s the directory in Step 12 above
  16. The drivers should now be fully installed.

Installing the drivers lets you connect your phone in debug mode.  This allows you to take advantage of the SDK tools, such as ddms which lets you take screenshots.  It also lets you easily install applications from your computer, browse files on your phone and if you start developing Android applications you can quickly test them out on your phone.

UPDATE: If the drivers don’t work for you then try using these drivers instead