Task Bar Management

Can anyone tell me where I can find some useful information about how to manage my Task Bar {on Windows XP Pro (SP2)}. All the HELP dialogues I have queried tell me what it is and how useful it can be, but I have yet to find a place that tells me how to invoke changes. This is particularily vexing because every once in a while I inadvertanylty do something that changes it, and I don't know how to get back to where I was. Also, I recently installed Iomega's Automatic Backup Pro and it put an enlarged icon in the Task Bar (even though the Backup Pro was not running). It looks like the kind of enlarged icon that appears when application is running (and muted when diminished), but with a difference. It is not functional. It doesn't act as a shortcut so that left clicking on it does nothing, and right clicking on it likewise does nothing so I can't even delete it. I really would like to know how to control the Task Bar for this and many other routine situations. Can you help?
Thanks.