answer:Please stop using WinXP. No OS that is no longer receiving security updates is suitable for use on the Internet. It’s only a matter of time before such a machine is compromised, and spewing spam emails or DDOS attacks at the rest of us. According to this site, “Chrome relies on the Windows certificate store. Unfortunately, it does not (currently) give any way of installing a certificate from a URL.” So, as you suspect, you won’t be able to fix this unless you can get a root cert update from your OS vendor. Please consider switching to Win7 or upgrading to Linux.