I'm afraid I've never really used IE on any of my regular systems, so I can't really say what you might have been doing wrong there.
However, the commands you listed in your post seem to do the following:
start up SMARTDRV - all this does is speed up disk access in DOS mode, if it doesn't work it won't affect your results.
delete c:\temp. As far as I know, IE has never kept any of its files in there anyway.
The directories you really want to delete are the later ones mentioned in the article: cookies, tempor~1 and history.
From what you've said it seems that for whatever reason you didn't actually make it that far?
What OS are you using? The deltree command certainly doesn't work on my Win2K machine, so it may be something like that...