Thank you for the incredibly quick response!
The SSL registration page worked perfectly, and I have been able to re-register without a problem. However, the other two links you listed came up the same as all the other avast pages. Specifically, Firefox shows a blank screen and IE states: "Internet Explorer cannot display the webpage. Most likely causes: You are not connected to the Internet. The website is encountering problems. There might be a typing error in the address." Needless to say, I am connected to the Internet, but I assume that everyone else is viewing the pages without any problem. No other pages are giving me this problem.
I'm going to run a boot scan on my machine in a bit. I'll report back the results when I get back online.
Again, thanks for all the help!
-Starchilde