Foreword: I know that this question has been already asked, but none of the solutions found here or on the web work for me. Problem: the PageUp and PageDown keys do not work properly, they actually behave as Back and Forward in History Please note that: 1) It is not a matter of caret browsing (tested) 2) Tried already with all plug-ins and add-ons disables, as well as in Safe Mode 3) The problem sometimes does not appear immediately (i.e., first page browsed after power up), but shows up after a few pages 4) The same problem appears in Thunderbird as well (PageUp and PageDown stop working) 5) Also the shortcuts CTRL-PageUp and CTRL-PageDown to switch across tabs stop working 6) I already uninstalled and re-installed Firefox several times (clean install). I also tried creating different profiles. Note: The profile that I am currently using uses a custom folder destination, not the default one - I don't think this can has any impact on the problem, but just in case.. Final note: The problem appeared when I moved from WindowsXP+Firefox4 to Windows7+Firefox5, it might well be related with W7, although nothing similar happens on other software (i.e., MS Word) Can you please help to solve this problem OR provide me a link where to download the good old Firefox 4 (at least I can test if the problem is related to Windows 7) Thank you Roberto