I am having some Internet connectivity issues, during which I able to access H.com but no other websites (or at least not many others that I check).

Any ideas why that is happening?

Because such is the will of Hashem. Gam zo l'tovah.

Are you using IE?
Try another browser, and make sure to close IE.

No, this was with Firefox, with the same results when I tried IE.

I tried unplugging the cable from my computer and the router, and replugged, and it began working again.

One of my roommates, the computer maven, thinks my Windows installation is a little screwed up, and that I should try rebooting. I'll try that later.

It's a sign...

Yep.

switch to linux.