browser cache\cookies, updating user\PW and deleting stored user\PW for the old site (Firefox has very good PW management, IE needs an extra program to get the overview, this program gives some control\overview over stored user\pw info in IE (may trigger your antivirus, false positive, no danger). Also, here's how to delete an individual user\PW in IE.
I don't understand a single word of the above!..... I have to say though, I have not had a single problem since the changeover. The whole thing has been seamless.