I changed my operative system in my computer to windows 7 and add several plugins to my mozilla firefox, and after that i couldn´t find the plus signal to open a new page in a new tab.So, everytime i opened a new page it oppened a new firefox window, and this was very boring.So, i tryed to open mozila in safe mode and tryed to add some extras and i think it was because of this that i started to have several boxes from java script application opening and telling about several errors everytime i open a new window in mozilla.The errors are the following: "error on adding toolbar element:NS_error Unexected, component returned failure code:0x8000fff (NS_Error_Unexpected)...id:places-New Place or:id:Plus-Circles or:id:Plus-Profile or:id:Wallet or:id:Web fonts error on adding menu element:NS_Error_Unexpected, component returned failure code:0x8000fff(NS_Error_unexpected) id:Places-New Place id:Plus-Circles id:Plus-Profile id:Wallet id:Web fonts id:" The problem now is that despite the errors appears all the time i open firefox, the good thing is that the plus signal now appears and i can open a new page in a new tab but that page opens at the same time in a new window!!! I mean the page appears in a new tab and in a new window and the errors are appearing all the time i open mozilla!What can i do to get rid of this???