I had a friend who was having trouble with all of the ssl enabled websites he visited in IE. Every site he visited was saying the certificate had expired. We checked settings all up and down IE and found nothing. Then we tried Firefox. Same thing. The best thing any Google search came up with is reinstall IE. After checking that all updates where installed I was stumped. Eventually the friend called and said he had figured it out. The date on his computer was set to 2004. I can't believe I did not think of something that simple. So setup those windows machines to sync to time servers. Double click on the windows clock. It's in there.