OldMike65 said:
AdwCleaner does not look for Malware on your computer. Here is a description of what it looks for and will remove.

AdwCleaner is a program that searches for and deletes Adware, Toolbars, Potentially Unwanted Programs (PUP), and browser Hijackers from your computer. By using AdwCleaner you can easily remove many of these types of programs for a better user experience on your computer and while browsing the web.
The types of programs that AdwCleaner targets are typically bundled with free programs that you download from the web. In many cases when you download and install a program, the install will state that these programs will be installed along with the program you downloaded. Unless you perform a Custom install, these unwanted programs will automatically be installed on your computer leaving you with extra browser toolbars, adware, and other unwanted programs. AdwCleaner is designed to search for and remove these types of programs.

I run AdwCleaner from time to time just to check my computer for anything that might have been installed without me knowing it. Does not do any harm in checking.
Thanks for the detail information. Can you think of something that why there is no problem after installing Firefox, because if it could be a adware or unwanted program or anything else than where it has gone now.