By default, Internet Explorer does not prompt to send a certificate if only one certificate is present. If a valid certificate matches site requirements, it is automatically sent. This is useful for basic users, for who authentication is transparent, but some users might need an alternative authentication.
To enable the prompt for certificate:
Step 1. Run Internet Explorer.
Step 2. Select Menu Tools.
Step 3. Select Internet Options.
Step 4. Select Tab Security.
Step 5. Select Local Intranet and click Custom Level.
Step 6. Find the Miscellaneous part and check Disable for Don't prompt for client certificate selection when no certificates or only one certificate exists.
Step 7. Click OK and OK again.
NOTE: Now when entering a Website asking for a certificate, you are prompted for a certificate selection. Click Cancel and you will enter the website anonymously.