Browsers are saying that something is not trusted.
The certificate domain name must match the URL you are visiting. Check again using 'View Certificates' to see if the domain name on the certificate matches the domain name in the URL that you are going to.
Check your Internet Option's and make sure that 'Use SSL 3.0' is selected in the 'Advanced' section.
Lastly, the certificate may not be installed correctly. This can be checked by clicking on 'View Certificates' when you get the error message and seeing if all three certificates are visible.