In IE9 and IE10, if the system shutdown unexpectedly (perhaps by pulling out the battery or disconnecting the power plug), on next reboot the IE9 in Windows7 and IE10 in Windows8 will forget the saved passwords, such as Gmail, Hotmail and other user preferences such as Bing region. My region is Australia. So by default it opens the Australia page. When I change it to US-English and restart the computer it always remember my preference. But the unexpected shutdown flashes the saved preferences and resets it back to Australia.
FF remembers that of Bing, Hotmail, Gmail etc. even if the system shutdown abruptly, crash unexpectedly or for any reason (without saving settings.. you can reproduce this bug easily)