Strangely, I cant PageDWN or PageUP

Only in Moz, my keyboard pageUP/DWN button stopped working this
weekend. It worked in other apps, and Moz B4.

The first time this happened I trashed User/Library/Mozilla/
preferences. This fixed the error, bit Moz lost my identity
preference. To reconnect Moz with my ID I used the Switch Identity
Menu. In the popup dialog, I created a new ID, Then choose the
existing identity folder. Everything was fine. Moz loaded my old ID,
PageUP/DWN worked fine, saved bookmarks, etc. FIXED.

TODAY I launched Moz and the PageUP/DWN was broken again.???!!?! I
trashed the preferences in User/Library/Mozilla/ But No effect. Then I
trashed a few user preferences User/Documents/Mozilla/User/blabla.
This time when I tried to reconnect Moz and my existing idnetity, when
I saved it, instead of using my existing identity, Moz created a new
folder INSIDE that folder.

WTF? I fixed this by replacing the contents of the folder with my old
data. This fixed the problem, but along the way I lost all my internet
passwords in one of the preferences.


1). Any ideas why the first time I was able to select an existing
Identity? (This buggs me, there should be a button to select an
existing ID.)

2.) What is the file name for password preferencs, so I can replace
this file from backup?
UPDATE= By trial and error, I found the offending keyboard preference=
"prefs.js". Deleting this preference fixes the scroll button BUT it
also deletes saved passwords! What can I do to save all my passwords
and still fix this scroll problem?

3.) Any ideas why the pageUP/DWN button would not work to begin with
in Moz? If its a bug, I have upgraded from Moz 1.6 to 1.7.
--
I'm on PowerBook Mac OS X.2.8."