Hi corc2. Diskeeper Lite is much much better than the Windows 98 defragger, but I don't really find it much of an improvement on the defragger built into XP, so I didn't bother to install it when I made the change. It's designed to be annoying to encourage you to buy the full version.
When I have a program that starts itself at bootup I often find that it can be disabled via the startupp list in Regseeker click here.
You may also find that you can disable it via Control Panel - Administrative Tools - Services