when i click a link on any web page< mozilla opens a new window instead of opening the link on the opened window?
when clicking on any link on any webpage a new window opens. Eg. On the bbc home page if you click "news" a new window opens instead of going to the news page of the web.
Please read this article to see if it helps:
Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).
See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems
If it does work in Safe-mode then disable all your extensions and then try to find which is causing it by enabling one at a time until the problem reappears.
You can use "Disable all add-ons" on the Diagnose Firefox issues using Troubleshoot Mode start window to disable all extensions.
You have to close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")