Why won't Facebook plug-in load anymore?

[frostproofgrapefruit]

I downloaded something that turned out to be malware, so I quickly rebooted my computer in safe mode, then uninstalled the program, along with a couple others that had been recently installed that I wasn't sure what they were. Now whenever I use Firefox, when I come to a webpage with Facebook commenting, the Facebook plugin won't load anymore. It works fine in IE and Chrome, but I prefer Firefox. Firefox is the up-to-date version on my computer. I like being able to comment on news stories, etc., and don't want to have to open the page in another browser just to do so...do you know how i can restore this feature? Should I uninstall and reinstall Firefox maybe? Thanks.
To be clear, I'm talking about websites outside of Facebook that use a Facebook plug-in for commenting...of course I have no trouble using the Facebook site itself.
I use Avast free, but it's annoying that after a scan for some files it says they cannot be scanned. I'll have to download Malware Bytes when I get home, but I don't know that it's due to malware, I thought it might have been that I mistakenly deleted a program that I needed for the plug-in to load.

[357]

Just uninstalling malware isn't enough. Did you run an anti-malware program?
~
https://www.malwarebytes.org/free/

Did you do a virus & spyware scan?

[Md Masud]

Scan ur computer