IF you use a different browser and the behavior changes, then it's localized to Chrome and perhaps a simple reinstall will fix it. If the other browser has similar HTTPS warnings then the first culprit is your Windows certificate storage (which Chrome doesn't trust by default but can cause problems like this). Is the other browser also shows this problem then we've got both local compromise and unsavory ISP options to consider.
Could go
through about a dozen options in ten minutes at the console but this way is tough. Hrmm.
It's probably something simple though, the paranoid options don't fit this sort of thing. You'd see it all over the place.
And, just to elimiate a whole CA storage problem in Chrome... any problems with
https://www.google.com ? -Magnus