Removing Network Assistant

I have a new Dimension 5150 and this is first time I have needed to strip software down rather than build it up for my use. Used XP's usual remove progs on Dell Network Assistant but this removal is incomplete. When I boot up Windows Installer tries to install it and suggests I use Dell Network Assistant CD to do this. When I do not respond gives a Error Message 1706. How do I remove this trace of Network Assistant?

It slows down booting up and I strongly dislike having anything on my PCs that is not being used as it can affect performance and security.

Thanks