I am at my witâ€™s end! I frequently get _certificate has been revoked_ for no\nreason. I even got it when trying to register for posting on THIS site!!!\n\nI have gone into Internet Options/Security and tried re-setting the security\nas low as it will go, to no avail.\n\nIt also happened when I tried to sign up for Instant Messenger â€“ I\ndownloaded everything, careful to use the version recommended especially for\nVista, but when I went to establish a screen name, I got the same message.\n\nThe sites I am having the problem with are not fly-by-night merchants â€“ it\nis places like Amazon.com, etc.\n\nOn the advice of someone, I tried the following, but the problem is now\nworse than ever - I can't even log into "My Google" homepage!!!\n\nÂ· On the Security tab, reset each of the zones to their default level.\n\nÂ· On the General tab, in the Browsing History section, click Delete. On the\nDelete Browsing History window that opens, delete your temporary internet\nfiles and also your cookies. When you do this, you may find that on some\nsites you need to reenter your username and password.\n\nÂ· On the Content tab, click the Clear SSL State button to clear the current\ncertificate state.\n\nClose Internet Explorer and then restart it.