Control the Auto Complete Mode

Start/Run/Regedit

“HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Explorer\AutoComplete”
Value Name: Append Completion, Data Type: REG_SZ (String Value), Value Data: yes or no. Create a new string value, or modify the existing value, named "Append Completion" and set it to "yes" to append the suggested text as you are typing or "no" to only show a drop-down list.

Restart Windows for the change to take effect.

Note: This setting also changes the auto complete functionality of Internet Explorer.