My grandson downloaded 'Yahoo Messenger with BT Communicator + Yahoo Internet Mail', when I wasn't watching him. I'm now unable to remove these sites. They are in add & remove in the control panel, but clicking the remove doesn't remove them. I use windows XP. Any suggestions please!

This program has been very useful in many different ways.

You can choose which programs load and which don't

RockXP - TweakUI

If your grandson loaded the programs recently, you can always use the System Restore feature in XP to restore the PC to a date before the programs were downloaded. This is the easiest way to resolve your issue.

I've also been very impressed with how SpyBot as "advanced features" to accomplish such things.

If you download SpyBot: http://www.safer-networking.org/en/download/

And you changed it from "Default Mode" to "Advanced Mode", you get an option for "Tools".

In tools, you can enable "BHOs" [Browser Help Objects], and you can disabled any tool bars, or browser plugins.

There is a ton of other features in tools also, that are very helpful.
I constantly moderate "Active X" to make sure that no keyloggers, or spyware is attached to my explorer.

The Resident Tea Timer is good for watching what gets installed and plugged into other programs: http://www.safer-networking.org/en/faq/33.html