Turn on command completion

To implement command completion requires using the registry editor, RegEdit, which when misused can render a computer or an account useless. So, follow this at your own risk.

1. Run RegEdit (Start > Run, type in regedit in the dialog box).
2. Go to the folder HKEY_CURRENT_USER->Software->Microsoft->Command Processor.
3. Double click the key value CompletionChar.
4. Change the Value Data value to the ASCII value of the key you wish to use for command completion. Not all keys work. The recommended value is 9 decimal which is <TAB>.
5. Quit RegEdit.

Reference

Enable Command Completion (Windows NT/2000/XP) at Registry Guide for Windows.