Problem: When trying to start Microsoft Certificate Services on my Server 2003 box, I get the following error:
A required certificate is not within its validity period when verifying against the current system clock or the timestamp in the signed file. 0x800b0101 (-2146762495).
Solution. The Root CA for the server expired and needed to be renewed. Within the Certification Authority MMC, I right clicked on my Cert Auth and selected “All Tasks†and then “Renew CA Certificate.†Followed the steps and was able to start the Cert Services again..