Your question is answered on our big parent Meta site, Meta Stack Overflow:
How can one link/merge/combine/associate two accounts/users? (Anonymous/unregistered/cookie or OpenID/registered)
[…] follow this procedure:
Set the email address of your registered account to the address used in your other account. Since email is not visible to anyone, this will confirm that you own both accounts.
Edit: Some people have had trouble with this step. If you have two registered accounts and cannot make the email addresses the same, an alternative option is to make a note in one of the profiles: "Please merge this account into ."
Flag one of your posts for moderator attention and ask for a merge.
If the details match, we will go ahead and merge with no further ado. If we feel we need more confirmation for some reason, we will either comment or email to tell you.
