Hide the Command Bar shortcuts only
1. regedit
2. HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\CommandBar
3. Create a new DWORD called Enabled with Value 0
4. close regedit

Removing the entire Command Bar
1. regedit
2. HKEY_CURRENT_USER\Software\Policies\Microsoft\Inte rnet Explorer\Toolbars\Restrictions
Important Note: The above branch does not exist by default. You need to create them manually
3. Create a new REG_DWORD value named NoCommandBar
4. Double-click NoCommandBar and type 1 as its Value data
5 Close regedit

http://www.winhelponline.com/articles/86/1/ has reg files to make life easier.