When you have a problem with a site that has been updated and previously worked fine, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Bypass Firefox's Cache

Use Ctrl+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

"3-bar" menu button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try reloading the page. Does that help?

I discovered what my problem was by starting Firefox 32.0.3 in Safe Mode with all addons disabled. MSN.com was displayed properly. The culprit in my case turned out to be an addon named "NoSquint v2.1.9". Disabling this addon allows Firefox 32.0.3 to properly display "MSN.com". I can now change my Homepage back to "MSN.com" although I don't really care for the new page, it is better than any other I have found.