What's supposed to happen is:

Firefox will check whether your address bar entry has spaces. If it has spaces, it will automatically be run as a search. If it doesn't have spaces, it will be tried as a URL first. If the URL is not found, then you might get search results as a backup.

So, for example, about:config can't have any spaces.

But.. if you find that even a short URL like abc.com gives you search results, we'll have to dig deeper and see why. One thing to try would be Firefox's Safe Mode. That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Thanks. I got the popup that said "you could void your warranty" so I guess I can get to the about:config in Safe Mode. However, I did try the abc.com and just typing in about:config again in regular Firefox mode before I did the Safe Mode and it gave search results. I guess for some reason it thinks that there is a space when there isn't. Anyway to get this to work the way it is supposed to so I don't have to completely turn the searching function off? It's just annoying when I need to go directly to a URL because it keeps sending me to the search terms pages.

To turn off address bar search, disable the "keyword" service using the steps in this article: Search the web from the Address Bar (section entitled"Turning off the web search in the address bar"). Does that fix it?

I tried to trouble shoot to see if it was some of my customization of Firefox that did it. Regardless if I go through and disable all my extensions, change my theme back to the default, it still gives search terms even when I type in a URL without spaces. I did try what was suggested in the article you referenced. I changed my preferences in safe mode and then exited and tried it. It still gave search terms so that didn't fix the problem. I'm wondering if this is some kind of setting on my Toshiba laptop because it does this for Google Chrome and Internet Explorer as well. Any other ideas?

When Firefox checks with your DNS provider whether an address is valid the DNS provider can dishonestly redirect Firefox to the site of its choice. You might consider changing from your current DNS provider (possibly your ISP?) to another one. Some free ones are OpenDNS and Google Public DNS.

However, first it's worth checking whether your ISP allows you to turn off this feature (some do, or at least say they do) and check whether this is actually your ISP's search results or possibly some malware/spyware that needs to be removed.

The ISP/DNS doesn't seem like the problem. My husband's laptop shares the same network and internet provider as my computer. His has never had this issue on Firefox, Chrome, or Internet Explorer....any browser. I will do a malware/spyware check asap to see if this fixes it.