Carefully fill in the form fields on the registration page. If you made any errors, they would be shown, and must be corrected, otherwise the letter with the link of registration confirmation will not be sent.
When registration was incorrectly specified your email address. In this case, the letter can not be delivered. Be attentive when you fill in the field "email".
The letter was delivered, but fell into the "Spam" in your mailbox. In this case, check not only the folder "Inbox", but also the folder "Spam".
On this page enter your e-mail address that you assigned to your account. Then you will receive a letter with a confirmation link. Click on link from an email. Next you come on mail a new password that can be changed if desired.
With a gross violation of the rules of the site, trying to automatic mass mailing to other users, ignoring site administration warnings, the account of the user will be blocked. There is a reference to the rules at the bottom of each page.
Look attentively, the answer to your question can be at this page in the list of possible questions. If there is no, check your email, and not only the folder "Inbox", but also the folder "Spam". Most likely, you have got the reply.