Cannot uninstall firefox setup 184.108.40.206
Are you referring to a file named "Firefox Setup 220.127.116.11.exe"? This file is an older installer for Firefox, and can be simply deleted by right clicking it and choosing Delete.
If it is an entry in Programs and Features, its probably nothing to be too concerned about. You can remove it with CCleaner (http://ccleaner.com/)
However, your Firefox version is out of date and vulnerable to many exploits. Please consider upgrading using Help -> Check for updates.
Firefox 3.0.10 is also an older version: Firefox 3.0.19 is the last from the no longer supported Firefox 3.0.x branch.
You should update to the latest 3.5.x or 3.6.x version.