1. Insert the Windows Vista Install DVD and reboot the computer
If you see a message about hitting a key to boot the DVD, do so. Otherwise, the PC will simply launch into Setup and display a black text-based screen with the message "Windows is loading files..." After that, you'll see the Vista boot screen and the screen will move into the initial phase of Setup.

2. Choose your language, time and currency formats, and keyboard or input method
For most people, the default values will already be correct, but make any needed changes and click Next to continue.

3. Install or repair Windows Vista
In this phase of Setup, you can choose between installing the OS ("Install now") or repairing a problematic, perhaps non-booting, Vista install ("Repair your computer"). Click "Install now" to continue.

4. Type your product key for activation ... or don't
After a brief pause, a screen appears in which you can optionally enter your product key and choose to have Windows automatically activate the OS installation (i.e. tie the product key to this hardware configuration). As per my advice in the Clean Install part of this series, do not type in your product key and do not let Windows automatically activation the install. Leave the product key field blank and uncheck the item titled "Automatically activate Windows when I'm online." Then, click Next to continue.

Because you have left the product key field blank, Vista Setup wonders if you're sure about this decision and asks if you'd like to correct your wicked ways and go back and enter the product key. Click No to continue.

Setup now prompts you to select the Vista version you have purchased. Be sure to choose the version you did purchase (Vista Home Premium, for example, is listed as Windows Vista HOMEPREMIUM), check the item titled "I have selected the edition of Windows that I purchased," and then click Next to continue. Be careful here: There are two versions of both Vista Home Basic and Vista Business listed; the versions with N at the end of their name are designed for the European Union only and do not include Windows Media Player 11. You almost certainly do not want to install these versions of Windows Vista by mistake.

5. Agree to licensing
In this phase of Setup, you must agree to the Windows Vista End User License Agreement (EULA). Check the item titled “I accept the license terms” and then clicks Next to continue.

6. Choose an installation type
Because there is already a version of Windows found on the PC's hard drive, Vista Setup will provide two options, Upgrade and "Custom (advanced)". Click the "Custom (advanced)" option to continue.

7. Where do you want to install Windows?
Here, you will see a graphical representation of your PC's hard drive(s), giving you the option to select a partition to which to install Windows Vista. Given the prerequisites for dual booting, you should see at least two partitions: One that contains XP and one that is empty and ready for Vista. For best results, select the Vista partition, click Drive Options, and then click Format. This way, we can be sure that the Vista partition is empty. (Note, however, that formatting the partition will effectively destroy any data stored on there.)

8. Installing Windows
As described in the Clean Install instructions, this phase of setup proceeds through four steps: Copying Windows files (almost instant), expanding files, installing features (blink and you'll miss it), and installing updates. After this, Setup reboots the PC. You'll see the "Windows is loading files" and standard boot screens, and then Setup will move into a text-like screen that says, "Please wait a moment while Windows prepares to start for the first time." Once that process is completed, you're dumped back into the Installing Windows screen, though it's finally progressed to the final step, Completing installation. Here, a basic set of hardware drivers for your particular PC are installed. Once this step completes, the PC reboots again.

9. Windows Boot Manager
If you were hanging around during the entire Installing Windows phase, you might have noticed the Vista boot menu, called the Windows Boot Manager, fly by quickly during the previous reboot. This time, however, you get to see the Windows Boot Manager in its default glory: It has two options, "Earlier version of Windows" and "Microsoft Windows Vista." The second, "Windows Vista," is selected by default, and a timer is counting down from 30 seconds. If you don't do anything in 30 seconds, Windows Vista will boot. Otherwise, you can hit ENTER to launch Vista immediately, or use your keyboard Up and Down Arrow keys to make another selection. Tap ENTER (with "Windows Vista" selected) to configure Vista for the first time. We will examine this boot menu in greater detail once Vista is up and running.

10. Set up Windows
As with Step 8, this portion of Setup is identical to the same section described in the Clean Install guide, so please refer to that article for more information. Basically, you must choose a user name, picture, computer name, and desktop wallpaper, configure Automatic Updates, review time and date settings, and select the network location (Home, Work, or Public Location, assuming your networking hardware was correctly detected during Setup). Then, Vista Setup thanks you and performs the lengthy computer performance check. After that, you can logon to Vista for the first time.

11. Initial logon
Now, you can enter the password, if any, for the user account you created during Setup and log on to Windows Vista for the first time. What you see here will depend somewhat on how well your hardware devices were configured and installed. Windows Vista will load the desktop, complete with the background you configured, and load the Windows Sidebar on the right side of the screen. The Welcome Center window will also appear, providing you with access to a number of post-install tasks, some of which we'll examine below. If your networking hardware was correctly detected, Vista will download and install any pending updates. These will include hardware driver updates, so if your networking hardware was not correctly detected, you should install those drivers first so that Vista can go and grab whatever other drivers it will find online.