Where does this 'secure credit numbers' come from, an add-on (extension) or how does it work? Please see our [[Using the Troubleshooting Information page]] article and post this information here, to enable us to give suggestions. Most likely this is an issue with the extension and Vista, so most likely you will have to report this problem back to the author of the extension - if it's an extension at all. If it is tied to a certain website or a program on your system, we will also need any information you can provide. I did find this information via Google: [http://www.discovercard.com/customer-service/faq/soan.html#q723 DiscoverCard Customer Service FAQ about 'other browsers'].