Nick,
I would think that if Comcast (as ISP) was the problem, more people would be complaining here. Worth a shot to talk to them, but don't be surprised if they say, "It's not us."
You have, up to this point not mentioned which browser you're using. Based on lacking knowledge on that point, let me make two suggestions. Uninstall your current browser completely, restart your computer, and then reinstall your current browser. Work any better? If so, problem fixed. If not, download another browser of your choice, Firefox, Chrome, Opera, SlimJet, etc., and then install it and go to OGR website. If new browser solves the problem, we're done again. If not, problem is probably not your browser.
So, let's check to see if you use Adobe Flash. Get to the Windows Control Panel and select Programs and Features to get a list of all installed programs on your computer. Check the list to see if Adobe Flash is there (it should be near top of list), and, if so, the version number off to the right of the name should be 21.0.0.213. If not, go to the Adobe website and download and install the update. Test to see if that fixes your problem.
If not, next, let's check your firewall and anti-virus program. You do have them installed, right? I know you've said nothing changed on your computer before the problem arose, but many people set these programs to update automatically, and that could be related to your browser issues. Try uninstalling each (one at a time) and then checking what the OGR website looks like. If you see that one or the other causes your problem, you can either switch to a different product or contact the vendor to see if they can help you solve the problem.
Other than these suggestions, I have no further clues. You could try the free upgrade to Windows 10, but I, myself, have been avoiding that til things look better, and I have no idea if that would solve your problem.
Good luck,
Chuck