The above thread relates to explorer.exe and not iexplore.exe, 2 very seperate programs, also the hang types do not match, the suggested corrective measures however could still apply given that 3rd party toolbars are often classed as PUP (potentially unwated programs) by most AV programs.
straight from the horses mouth,(don't look at it there though) marylin from microsoft,
answers.microsoft.com/en-us/windows/forum/windows_vista-performance/windows-explorer-freezing-problem-event-name/0c136176-32dd-46e6-a1a9-e05d69d7e024
or :
bypassing anything technical with windows xp.
Edit:
there may be trojans, mallware or viruses.