Yep you can't uninstall IE from Windows XP
However...
Microsoft has made it possible for OEMs, administrators, and users to remove user access to Internet Explorer while leaving the Internet Explorer code intact and fully functional to make sure the functionality of programs and operating system functions that rely on it. For example, Windows XP supports an "IEAccess=off" switch in the Unattend.txt file, and Internet Explorer has been added to the Add/Remove Windows Components section of the Add/Remove Programs tool in Control Panel.
So what you can do is block access on a users machine to IE but still have the components available for everyday use.
In Charly's case, he could (as admin) disable access to IE on user a,b or c's computer and still allow updates of any virus utility through the network.