security certificate is really ok but I am told it is not

I tried to go to different sites and I am told the security certificate is bad or expired. That happens no matter what browser I use.

I go through the process of doing an override. Even that does not work all the time.

For example when I try to log in to a bank site, it says the sec cert is bad. I choose to continue anyway. I put in my login information, and it just hangs there

When I choose view the certificate it displays a certificate that has NOT expired while it INSISTS that it has expired.