Netscape mail launched from IE

My sister is having a problem with Netscape Mail being launched on some button options on the main toolbar. She want Outlook Express to launch. OE *IS* set as the default but Netscape Mail is overriding in some cases, as explained in her note:

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When I click on the Mail icon in my tool bar, 4 options come up: Read Mail, New Message, Send a Link, Send Page. When I click Read Mail it opens up Outlook Express, as it should. But when I click on any of the other three, Netscape Mail opens up. There must be some association somewhere to change, but I can't find it. IE is set as my default browser now, so that's not the problem. If you know how to fix this, let me know. It's Netscape 7.02, in case you need that. Outlook Express is 6, and IE is 6.0.2800.1106 (sigh, could they make the version any longer!). *** end cut ***

Any ideas why one button launches OE as it should, but others don't?

thx,

 

Yeah... that's the first thing I suggested too, but also figured it was ok, since she does get OE when clicking one of the buttons.