Adjusting AutoComplete Settings:
To modify your settings for the AutoComplete feature or clear all items from the list
of form or password suggestions, follow these steps in Internet Explorer:
1. On the Tools menu, click Internet Options.
2. Click the Content tab.
3. Click AutoComplete.
4. Click the appropriate AutoComplete check boxes, or click Clear Forms or Clear
Passwords to clear all saved items from the appropriate AutoComplete history.
Click OK, and then click OK.
If you have done the above and still have a problem:
Outlook Express keeps prompting for your password - Fix
http://www.dougknox.com/xp/tips/xp_oe_passwords.htm
This fix also applies to Outlook, other programs that store passwords
in the Protected Storage System Provider sub-branch of the Registry.
It also corrects some issues with Internet Explorer and AutoComplete.
[Courtesy of Doug Knox, MS-MVP]