Make a System Restore point first, then go into the Registry (type regedit in the Run command box via Start menu). Use the Edit, Find command to search for strings containing any references to the ISDN router and delete them. Take care with the Registry, hence the Restore Point.
I've tried deleting through msconfig but I can't seem to identify the name. Nothing looks like it. I'm a bit nervous about editing the registry. I've searched for any reference to ISDN and there are loads. The System Restore point doesn't always work on my computer, I have been told this is a common fault with Windows ME (but that's another story).
If you just wan't to get it out of your System Tray click Start,control panel scroll down until you come to "Taskbar and Start Menu" double click on it In the window that appears click on "taskbar" tab now click on customize there are to columns Control and behaviour find your icon and then click in the behaviour column a drop down list box will appear click on "always" click on apply and back out of the window this will stop it appearing in your tray.