Creating a captcha system using XAMPP involves combining PHP, HTML, and a little bit of JavaScript. Captchas are used to verify that a user is human and not a bot, helping to prevent spam and automated attacks. Below is an example of how you can implement a simple captcha system using XAMPP:

1. First, ensure you have XAMPP installed and running on your system. You can download it from the official website and start the Apache and MySQL services.

2. Create a new folder within the "htdocs" directory of your XAMPP installation. Let's call it "captcha_demo."

3. Inside the "captcha_demo" folder, create two files: "captcha.php" and "verify.php."

4. Open the "captcha.php" file and add the following content:

```php

session_start();

// Generate a random captcha code

$captcha_code = substr(str_shuffle("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"), 0, 6);

$_SESSION['captcha_code'] = $captcha_code;

// Create an image with the captcha code

$image = imagecreatetruecolor(100, 40);

$background_color = imagecolorallocate($image, 255, 255, 255);

$text_color = imagecolorallocate($image, 0, 0, 0);

imagefilledrectangle($image, 0, 0, 99, 39, $background_color);

imagettftext($image, 20, 0, 10, 30, $text_color, 'path_to_your_font.ttf', $captcha_code);

// Output the image

header('Content-type: image/png');

imagepng($image);

imagedestroy($image);

?>

```

Make sure to replace `'path_to_your_font.ttf'` with the actual path to a TrueType font file on your system.

5. Next, open the "verify.php" file and add the following content:

```php

session_start();

if (isset($_POST['captcha_input'])) {

// Retrieve the user's input from the form

$user_input = $_POST['captcha_input'];

// Retrieve the captcha code stored in the session

$captcha_code = $_SESSION['captcha_code'];

// Compare the user's input with the stored captcha code

if (strtolower($user_input) == strtolower($captcha_code)) {

echo "Captcha verification successful!";

} else {

echo "Captcha verification failed. Please try again.";

}

}

?>

```

6. Now, create an HTML form that will display the captcha image and allow users to enter their response. Create a new file named "index.html" in the "captcha_demo" folder with the following content:

```html

Captcha Demo

```

7. Save all the files and open your web browser. Access the captcha demo by navigating to `http://localhost/captcha_demo/index.html`. You should see the captcha image and a text field for the user to enter the captcha code.

8. When the user submits the form, the "verify.php" script will compare the user's input with the stored captcha code. If the input matches, it will display "Captcha verification successful!"; otherwise, it will show "Captcha verification failed. Please try again."

This is a basic implementation of a captcha system using XAMPP. You can further enhance the security of your captcha by implementing additional features like time limits, session expiration, or more complex image distortion techniques. Keep in mind that captchas should always be used in combination with other security measures to ensure the best protection against automated attacks.