When the error with DSL occurred, it might be that Mozilla saved the past browsing session. Mozilla might have saved the "N" favicon in the history. When the session was restored, "N" icons dominated all the pages.

Running a new session might solve this problem!

Perhaps I do not fully understand what you mean by running a new session. That would be an issue on my end not yours given the internet classes at the senior center didn't exactly cover much more than the basics.

I did restart my computer again (very old and running XP) and did attempt to open up firefox to my home page and even the home page favicon still displayed NetGear's N. I attempted to clear my cache using CCleaner then restarted the computer again and again attempted to open Firefox. Same thing happened to my home page. When I attempted to open new tabs with sites in my favorites from the drop down bookmarks menu, they did open however they're not displaying the favicon I know to be associated with the bookmarked website. I should add that some sites from my bookmarks, such as the CDC, have been opening up with a dashed little square as the favicon as opposed to the blue N. So far, the only sites displaying the appropriate favicon are those mentioned previously, (Google Maps, Mozilla Support, and Restoration Genetics) .

Thank you for trying to help me.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of the involved files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.

Ah. I haven't a clue how to back anything up however I did find where the history was and right clicked on a familiar site and did use the "Forget About This Site" feature. I then went to the corresponding page and refreshed the page and voila, the N was gone and replaced with the actual favicon. I did that about ten more. Each time, the N was replaced with a correct favicon.

For whatever reason, I decided I'd try refreshing a page that I hadn't first used the "Forget About This Site" feature on. Interestingly enough, a correct favicon displayed so I tried another. The next displayed properly. Then another. Each time I reloaded a page, the correct favicon began displaying. I had tried that before registering here for help and it didn't work yet this time it did. I have no idea why refreshed pages began displaying the correct favicon without first visiting the history and doing as originally instructed but... they did.

I cleared my cache then restarted my computer. Much to my surprise, all of my bookmarks were present and in the order I had them. I don't believe I lost a single password. Right now, I can see all the correct favicons in both the bar and the drop down menu of all open tabs. I believe it's time to count my blessings and call it a day.

Thank you Anik124 and thank you cor-el for steering me in the right direction.