Malware will perform a variety of nasty activities that can cause the dialer to slow down or worst, stop working properly.
Symptoms are but not limited to:
- The Admin page never finishes loading or can't load certain pages.
- The Agent dialer page, slows down, crashes or hangs a lot.
- Floods your browser with pop-up advertising.
- Hijacks your searches and redirects you to an advertising or a phishing web page.
- Your home page has been changed to some weird looking search page.
- Your browser keeps opening many tabs or windows.
- Unwanted toolbars or browser add-ons have been installed.
- Slows down or crashes your computer.
- Slows down your internet connection.
Examples given are different at times but if you have one or several of these, you may have malware present on your computer. Running a scan using your Antivirus software should be the first step in resolving this issue
Firefox Support provided a good article on how to resolve issues caused by malware. You may check this link for more information
Troubleshoot Firefox issues caused by malware http://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware