|Internet explorer can give a certificate error if the date is way off. So make sure your date and time are correct. You may need to install a new battery on the motherboard.|
"This error occurs when the current date is either before or after the time period during which the certificate is valid. Websites must renew their certificates with a certification authority to stay current. Outdated certificates can be a security risk."
Where 'current date' is whatever shows on your computer. So if that's off by too much it will fall outside the date range allowed by the website's certificates.
Anyway, check that and post back. If that's not the reason you may need to adjust some of the security options in 'internet options'.