Well, you can eaisly change your username in your Profile under the "Account Related Settings" > "Name" Field. This will change your displayname that we see.
As for your other account, you should have tried to contact me. Since I am an administrator here, I can update your email address or reset your password for your other account if you want to continue using it.
If you are thinking about chaning your display name to the same name as your other account, then I am sure it will not let you do that. So I'll need to either remove your other account, or change its display name so that it does not conflict.
Regards,
BigMike
