IE 8.0 not functioning properly after installing Norton Internet Security 2012

I just downloaded and installed Norton Internet Security 2012 v.19.5.1.2 on a Windows XP SP3 Dell XPS M1210 notebook running Internet Explorer 8.0. I am writing this message using Firefox, which seems to work fine. IE does not.

 

In Internet Explorer, I observe the following incorrect behavior. (1) The captcha for registering as a user on this forum is not visible; (2) loading Facebook reveals the page header and nothing more; (3) videos on espn.com and youtube.com show up as black boxes.

 

I have temporarily disabled Norton's Smart Firewall and pop-up blocking. I also used Control Panel >  Internet Options > Advanced to restore IE's default settings. None of these measures solved the problem.

 

When I first opened Firefox, I opted against a number of prompts from Norton, but I did not write down what they were about.

 

Can someone please help me restore IE to working order. Thank you in advance.