Troubleshooting: When I create a new record, information from another, unrelated account is auto filled into the new record.

This sounds like a problem with AutoComplete.  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, to adjust AutoComplete settings:

1. In Internet Explorer, on the Tools menu, click Internet Options.
2. Click the Content tab.
3. Under Personal information, click AutoComplete.
4. Uncheck the box for "Forms."