Most well behaved programs also come with an Un-installer that you can run
from the Add/Remove Programs control panel.
If you can't find the un-installer for the toolbar you want to remove then
get your hands on some spyware programs (freeware) which will remove it for
you.
Manual Procedure:
Start Registry Editor (Regedit.exe)
Go to the following location and check each GUID sub-key. One of which is
the malware toolbar entry:
HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Extensions
Also, check here:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Extensions
{check the values in the right-pane to identify the malware toolbar.)
Spot the entry and delete the appropriate key (backup the registry first)