Everytime I open Outlook Express I get the following message: "Outlook Express is not currently your default mail client. Would you like to make it your default client?". I click Yes everytime and it never makes any difference. If I click on an email link it opens about 20 windows and locks up my PC.
Anyone else had this trouble before?

Yup, had this with our work PC's after installing Office XP although that may or may not be related to the problem but the symptoms were the same.

Basically the fix was to go into Control Panel, Internet Options, Programs tab
Change the email preference to some other program on the list (doesnt really matter what) Ok that and test it (by opening an IE page and clicking on email).

Once thats done, you change the default back to OE, either by opening it and setting default or using the Internet Options in control panel, should resolve it though