This forum is for BPOS Live Meeting. Your question appears to have something to do with Internet Explorer. Here is a knowledge base article I found
http://support.microsoft.com/kb/290345 otherwise your question might be best answered in an XP forum.
Vickie - BPOS Technical Support
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If you click Clear SSL State on the Content tab in the Internet Options dialog box, you can remove all client authentication certificates from the Secure Sockets Layer (SSL) cache.
In an SSL session (using https://), when a server asks for a certificate to verify that you are who you say you are, the chosen certificate is saved in a cache. The chosen certificate can remain in the cache until you restart your computer. Clicking the
Clear SSL State button removes all certificates from the cache without having to restart your computer.