Microsoft released Windows XP hotfix KB893357 in April 2005 to add support for the Wi-Fi Alliance WPA2 certification for wireless security to the Windows XP wireless client. The new WPA2 certification replaces the older and less secure WEP certification, which is vulnerable to cracking software used to sniff and decrypt the keys. WPA2 adds stronger encryption and authentication systems, and became mandatory in 2006 for hardware to be certified by the Wi-Fi Alliance, ensuring it is available in all modern wireless networking equipment.
Open the Microsoft website in your Web browser, and type "KB893357" into the Bing search box. Click the magnifying glass icon to search, and then click on "Download Details: Update for Windows XP (KB893357)" from the search results.
Download the "WindowsXP-KB893357-v2-x86-ENU.exe" file from the knowledge base page, and click "Run" to launch the file when it has finished downloading.
Follow the prompts to install the KB893357 hotfix. Reboot the computer once the hotfix has installed to complete the installation.
If your network card does not support WPA2, it will not be available as an option after installing the patch. The KB893357 hotfix is included as part of Windows XP service pack 3.