Ann Dunham replied:

To help others who follow this hint, the first thing I had to change in the
user.js file was that the Firefox Address Bar search was turned off.

The next problem I had with the GHacks user.js was that Google Gmail
doesn't like it one bit.

Logging into Google Gmail brings me to this page:
https://support.google.com/accounts/answer/61416?hl=en

It looks like the GHacks user.js turns off cookies, so, searching for that
option in the user.js file, I find this:
// 0=allow all
// 1=allow same host
// 2=disallow all
// 3=allow 3rd party if it already set a cookie
user_pref("network.cookie.cookieBehavior", 2)

So I change that to:
//WIP user_pref("network.cookie.cookieBehavior", 2)
user_pref("network.cookie.cookieBehavior", 1)

Then Google Gmail worked!