All we have is what you wrote. Here's some priors on this one.
https://www.google.com/#q=can+only+access+https+sites+windows+8
I don't have any new findings on this.
We have comcast as an ISP. At any given time at least 1 Mac computer and 1 Windows 8 computer are connected to the network. The mac (which I am typing this on right now) is having no issues; there are currently two macbooks connected with no issues; the comcast tech who came to check the modem saw no problems, and his windows laptop connected with no problems. I usually have the windows 8 pc connected via wifi, but connected it via ethernet as well and the same problem persists. I also tried googles dns settings as it seemed to be a dns issue, but to no avail. I even tried the tips recommended in this youtube video: https://www.youtube.com/watch?v=1iAM5N_ySRo
Anyone have any ideas of what to do?

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