Aha...just had another squint at your miniscule screenshot and it's not a toolbar after all - it's the Common Pane that's added your windows folders, e.g. the File and Folder tasks, Other Places, Details etc bit that shows up when you open My Documents.
You'll need to change the PersistMoniker value in your registry. One way is to locate the hidden file desktop.htt (usually located in C:\Documents and Settings\General User\Application Data\Microsoft\Internet Explorer where General User is the profile name - do a search and you'll find it) and simply delete it. When you reboot, Windows will create a new default version for you.
Alternatively, copy the following highlighted text into Notepad and save it with the extension .reg
e.g. fixcommonpane.reg
Then locate that file and double-click it so that it merges with your existing registry.
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\CLSID\{00021400-0000-0000-C000-000000000046}\shellex\ExtShellFolderViews\{5984FFE0-28D4-11CF-AE66-08002B2E1262}]
"PersistMoniker"=hex(2):66,00,69,00,6c,00,65,00,3a,00,2f,00,2f,00,25,00,75,00,\
73,00,65,00,72,00,61,00,70,00,70,00,64,00,61,00,74,00,61,00,25,00,5c,00,4d,\
00,69,00,63,00,72,00,6f,00,73,00,6f,00,66,00,74,00,5c,00,49,00,6e,00,74,00,\
65,00,72,00,6e,00,65,00,74,00,20,00,45,00,78,00,70,00,6c,00,6f,00,72,00,65,\
00,72,00,5c,00,44,00,65,00,73,00,6b,00,74,00,6f,00,70,00,2e,00,68,00,74,00,\
74,00,00,00
If none of the above works, then this should. Copy the following highlighted text into Notepad and save it with a .vbs extension
e.g. fixcommonpane.vbs
Locate the file and double-click it to run
p1="HKEY_CLASSES_ROOT\CLSID\{00021400-0000-0000-C000-000000000046}\shellex\ExtShellFolderViews\{5984FFE0-28D4-11CF-AE66-08002B2E1262}\PersistMoniker"
p2="file://%userappdata%\Microsoft\Internet Explorer\Desktop.htt"
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.RegWrite p1, p2, "REG_EXPAND_SZ"
X = MsgBox("Log off/log on or Reboot for the change to take effect.", 4096,"Finished")
Set WshShell = Nothing
N.B. in both cases, the line that contains the HKEY reference should be one continuous line, i.e. no wordwrap. I'm sure you can figure that out :D