Had to reinstall Firefox after downloaded a 'make Firefox faster' option appeared from Mozilla as it completely crashed my internet accessibility. Message kept repeating I needed a proxy server address as Firefox connects via a proxy server. Had to finally resort to ATT to get me reconnected as update had changed my settings in Lan: all checked. Now if I try to download an add on it says it is installed, but is not - 41 acceptable add on - and if I click on tools> options Firefox crashes wi/no crash report window appearing; have to re click icon. Ditto options in menu. And will not accept click on options in customize, a hand appears and zero happens. Don't have ability to set my preferences, obviously. None of the sidebar options appear any more. I have no ad blocking evne after downloading and running ad block for 41. Firefox also crashes repeatedly. Have tried restart in Safe Mode, no difference. I am using XP and as many others have no interest in changing to 7 or 8 as long as laptop continues to function.