Many programs can send information as an email message. For example, you can send a spreadsheet to a mail recipient in Microsoft Excel, or click an email link on a webpage. If you have more than one email application on your computer, the only way to make sure these actions use a particular application, such as Outlook, is to set it as your default program.
The following steps set Microsoft Outlook 2010 as your default mail program.
Click the File tab.
Under Start up options, select the Make Outlook the default program for E-mail, Contacts, and Calendar check box.
Note: To send messages, an email account must be added and configured in your Outlook profile.