I see from your screen shots that you have MSN messenger running in the background. Do you have it on all the time? Do you still have the messenger service enabled? And have you tried killing all unnecessary processes under task manager and then surfing to these sites to see if it still asks for passwords? First I would turn MSN messenger off and try to see if it will let you in without the passwords. You could also try uninstalling netscape since that is when your troubles started...or use the go-back function from windows.

Good luck.