Remove your cached user credentials in Wireless Authentication

To remove your cached user credentials that are used for PEAP authentication,
remove the HKEY_CURRENT_USER\Software\Microsoft\Eapol\UserEapInfo registry key.
To do this, follow that steps:

Start, and then click Run.
In the Open box, type regedit, and then click OK.
Locate, and then click the bellowing registry key: UserEapInfo
Then Delete it.