PEAP authentication is not successful
Users using Microsoft Windows XP Service Pack 2 (SP2), may experience problems when authenticating or re authenticating to the wireless and wired 802.1x networks. Sometimes the initial connection may authenticate successfully, but subsequent authentication attempts may not connect successfully. This is because of a Microsoft bug affecting Windows XP SP2 users. The bug is documented in Microsoft knowledge base article KB885453
Microsoft has released a free hotfix to address this issue. To download the hotfix please visit http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=885453&kbln=en-us .
Installing the KB885453 Hotfix
1.Fill out the form at http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=885453&kbln=en-us and click the 'Request Hotfix' button. This will send you an email with a link to the download and a password to use to install the fix.
2. Click the link and download the file to your computer.
3. Once the file downloads, double click the icon.
4.When you see the 'Microsoft Self-Extractor' window, click the 'Continue' button.
5.Click the button with '...' on it to choose a download location. In the new window, select 'Desktop', then click 'OK' on both windows.
6.Enter in the password you received in the email from Microsoft.
7. This will extract a new file to your desktop called 'WindowsXP-KB885453-x86-enu.exe'
8.Double click this new file to install the fix.
9.Click the 'Next' button on the setup wizard.
10.Click the 'I Agree' radio button and click the 'Next' button.
11.After the installer finishes, click the Finish button to complete installation and restart your computer.