Open your email client. This is the program that you use to send and receive email. This can be a program like Microsoft Outlook or Windows Live, or your Web browser if you have a Web email account.
Click "Compose" or "New Message" to open a new message window.
Type the recipient's email address--one you know to be valid and working--into the "To..." box. Give the message a subject and a brief body. Click "Send."
Click "Inbox." If the message you tried to send immediately shows up in your inbox, that particular recipient is blocking your email address.