My home page (www.gmx.co.uk) opens with no problem but I am unable to open a new tab from either the "+" beside the open tab or the File menu. Firefox Help does, though, automatically opens with a new tab. The problem appears to be confined to one profile - infortunately my work profile - where I would normally have 4 or 5 tabs open whilst working. My personal profile (home page www.BBC.co.uk/news) seems unaffected. For the time being, I am working round the problem by opening a series of 'Help' tabs to give me my workspace.