The first part of your question, autocomplete, is answered for you in IE help:
To adjust AutoComplete settings
You can configure AutoComplete to save and suggest only the information you want. You can choose whether to use AutoComplete for Web addresses, forms, and passwords, or not use it all. You can also clear the history for any of these.
In Internet Explorer, on the Tools menu, click Internet Options.
Click the Content tab.
Under Personal information, click AutoComplete.
Select the check boxes for the AutoComplete options you want to use.
I'm sorry I cannot help you with your other problem.