I just recently changed out my motherboard and every since then I have to constantly add a security exception on firefox to every site I go to and it only lasts like a day. Here is a picture of what one looks like from google. http://www.lib.utulsa.edu/images/Cert_Firefox2.jpg
I had tried the Time/date issue. It was wrong so I assumed that would have been the issue but it wasnt. I actually hadnt tried reinstalling, I kinda assumed that would be a fix but theres that thing inside you that wants an actual "heres the problem" fix. I'll probably try that though later when I get home.