A Firefox search bar virus has taken hold of my system and wont let go! Is there any way I can avoid uninstalling Firefox every day to get rid of this?

Question

The situation: Whenever I go to use the address bar or the small search toolbar (which is set to google) in my window, the search engine used instead is "search.searchcompletion.com", which returns very shitty search results and is annoying.
The things I have tried to fix this:
First, I disabled and deleted all my add-ons, changed my homepage back to google and updated my search engine to google. Tested search bar, *still infected* RESULT: NEGATIVE
Second, I downloaded a anti-virus/anti-malware program called Malwarebytes. It did good, catching 28 virus's in various files, quarantining them, and deleting them. I tested the search bar, *still infected* RESULT: NEGATIVE
Third, I read about typing in "about:config" into the Firefox address bar and changing a few things, as explained <a href="http://deletemalware.blogspot.com/2011/09/remove-startsearch-and.html">here</a>. I tested the search bar, *still broken*. RESULT: NEGATIVE
Fourth, I read you can "manually delete the virus from your registery". I followed the instuctions carefully, deleting these strings: HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main “Start Page”
HKEY_CURRENT_USER\Software\Policies\Microsoft\InternetExplorer\Control Panel “HomePage”. Tested the search bar, *still infected* RESULT: NEGATIVE
Fifth, someone somewhere installed a special add on that blocked certain sites. Whatever I did it did not work, the site (search.searchcompletion.com) just lost it's formatting, but still did not let me search using google. RESULT: NEGATIVE
Fifth, I just uninstalled everything having to do with Firefox from my computer. I reinstalled it and tested the search bar and it worked!....
For 24 hours. When I turned on my computer today, the search.searchcompletion virus is back, and short of uninstalling Firefox, I do not know what to do.
I have no add-ons.
I have deleted temp internet files
I have virus protection
I have tried everything.
Help me.

Answer 1

Plugins usually are installed externally to Firefox. However, you can disable them in Firefox so that Firefox does not use them.
SearchReset is supposed to automate the task of resetting certain preferences, but you still can edit them manually if necessary.
'''''Address Bar Search'''''
(1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful.
(2) In the filter box, type or paste '''keyword''' and pause while the list is filtered
(3) Right-click '''keyword.URL''' and choose Reset. This should restore Google as the default for address bar search.
Does that work?
'''''Search Box'''''
Usually it works to choose your preferred search engine from the drop-down. To remove an unwanted search engine plugin, usually the Manage Search Engines... choice at the bottom of the drop-down takes care of it.
Do either of those work?
There might be another way to hijack that search box; I think some of the other frequent responders probably are more familiar with it than I am.