I also thought that it might be due to some plugin etc.., but as I mentioned in my previous post, "Tried with another PC -- same !!".
Anyway, the problem seems to be gone now !! 
Still no clue, why it existed and how it vanished all of a sudden !!! I didn't install/remove any FF plug-ins during the last couple of says. ( I have XP/XP dual boot and I use only one of them for testing FF plugins and things like that. )
Thanx for the time you spared for me,
shabbir.