I am guessing that you are using different Operating System User Accounts. For instance you and your wife possibly log-in with different User Names and Passwords, and could have many differences in some of the Operating System (Windows 7) preferences. [http://windows.microsoft.com/en-US/windows7/Create-a-user-account see] <-- MS link may have different language options -- Without further information it is difficult to offer advice, but try in [[safe mode]] and also look at [[basic troubleshooting]] and [[firefox hangs]] <-- KB articles links often in differing language locales options -- should default to match language of firefox browser. You will have to try from each firefox Browser shortcut in turn, they will each use a differing [[profiles|profile]] which is one reason they may behave differently from as you put it each ''side''.