Outlook Express keeps making itself my default mail program

I used to use Outlook Express as my mail program with Win '98. I have IE 6.0 and Office 2000 running and now use Microsoft Outlook. Everytime I try to send a page from the web, my mail program has defaulted to Outlook Express. I go to tools, options, programs and change back to Microsoft Outlook. Next time it has changed back to O.Express again! Is there something I'm not doing right? This has just been a problem the last month. Can't think of any other changes I've made.

Thanks

 

These might help:

Default mail handler

more default mail handler

(if they don't, you get your money back).