Default mail client not properly installed.

This is Windows XP computer. Since past couple of weeks I was facing the error message mentioned in the title, i.e. ‘Default mail client not properly installed.’ I use to get this error every time I click any email address on this computer. After doing some research I came to know that we need to set default email client by going into control panel > internet options > select an email client which is Windows Live. I use Windows Live Hotmail for mailing purpose.

After doing this finally that error message disappeared but now there is a new problem. Now I get a new error message saying “.net passport”. What is it? How to get rid of this?

You can get more info about Net Passport on Microsoft website, as far as the error message is concerned, you just need to go into 'User Accounts' app in Control Panel, click on your account name icon. Here you will find an option to saying "Change my .Net Passport". Click the same and make the necessary changes.