How do i set up my default mail client on windows 7

Win 7 has no default email client, they did away with Outlook Express. You will have to install a second party application like Windows "Live" to get an email client. Outlook Express was too simple and worked too nicely for the average person, so they had to inflate it into a huge bloated program that is really cool for power users and corporations, but more than vast majority of home users will ever need, or ever figure out how to use.