That is me. But then when I registered it doesn't show my other posts from that account which is supposed to be this account.
Please see the Help page on merging accounts.
If you used the same credentials to create the registered account as the unregistered, then the system should have detected that. Even if it didn't, if the email addresses associated with the accounts are the same then the unregistered account may get merged into the registered account at some point. (I think that still happens.)
However, the way to ensure that the accounts are merged is to ask the Stack Exchange community management team to do it; moderators can't.