Where have I been? In my normal habitat, so to speak. I understand your net problems rather well, about a year or more ago an antivirus program update pulled the same trick on me, each and every time I had to log in to places, it didn't memorize anything no more, it even messed up something with the OS. It was even more frustrating that the only fix was format C:!
After major equipment overhaul there have been other setbacks (so called technical progress), but logging in and saving passwords works fine.
I agree with Dave that you might be having problems with your ISP on top of all, does it affect MT in some way? Is MT connection showing any malfunction? Is the connection to broker stable?