First off, why are you still using Internet Explorer?
Secondly….WHY ARE YOU STILL USING INTERNET EXPLORER?!?!?
Just kidding. So you’ve changed your webmail password and Internet Explorer won’t update the password stored in it’s Auto Complete. Well here’s the rub – IE has stored the password in your registry in an encrypted form. Gates forbid you could just open the registry, find the website you changed the password and modify that registry entry.
1. Close Internet Explorer.
2. Click on Start / Run… (or hit [START]+R) and in the run field type regedit (you will need to have administrator rights to edit the registry).
3. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\IntelliForms\Storage2
4. In the left window pane, select the Storage2 key, then from the menu, select File / Export and save the key to your Desktop with the File Name: oldstorage.reg
5. In the right window pane select all values (except for Default) then press Delete and select Yes to confirm value delete. Minimize Regedit.
6. Open Internet Explorer and visit the web site whose password you want to save. When Internet Explorer asks if it should remember your password, answer Yes.
7. Logout of site and close Internet Explorer.
8. Return to Regedit and press F5 to refresh the list. Now, select the Storage2 key, then from the menu, select File / Export and save the key to your Desktop with the File Name: newstorage.reg
9. Select the Storage2 key again, then from the menu, select File / Import and select the oldstorage.reg file (from the Desktop), and click Open to merge the data back into the registry. Click OK to acknowledge merge was successful.
10. Select the Storage2 key again, then from the menu, select File / Import and select the newstorage.reg file (from the Desktop), and click Open to merge the data back into the registry. Click OK to acknowledge merge was successful.
11. Close regedit.
Now all your previously saved passwords will be preserved without wiping out the site you just created.
* “commandeered” from http://www.watchingthenet.com/how-to-force-internet-explorer-7-to-save-web-site-password-after-answering-no.html
** this was originally written for IE 7, but here in IE 9 it still works