I have a server running on windows server 2008. Recently we created a domain and added it to the domain. Also it is promoted as an additional domain controller on the network. A domain user account was created with same username and password as my previous local administrator account. Now I unable to login using my local account. I tried loggin in using SERVERNAME\Username, but it is giving incorrect password error message. Is there any way I can retrieve or create a new local administrator account on a domain computer
Is the machine a Domain Controller? If so, you lose the ability to log in as a local account. You would have to demote the DC in order to log in as a local account.
Domain Controllers do not have local accounts. They "become" the domain in many ways. If you need settings or files from the old profile, it should still be in the Users directory.
Login on the machine using a domain admin account. Go into the Computer Management snap-in (compmgmt.msc from the command line). Drill down to System Tools | Local Users and Groups | Users. In there you can create a new local admin account or reset the password for you existing account. If you create a new account, be sure to add them to the Administrators group.