I installed SQL Server 2008 R2 to my local machine. But, I can't create a new database because of rights (or lack of).
"CREATE DATABASE PERMISSION DENIED"
So, I tried to assign the admin privileges to my current login
"User does not have permission to perform this action."
I also tried to create a new login that would have admin privileges but with no luck. How do I grant myself admin rights so that I can create a database? I can re-install, but I prefer not to.
Yes - it appears you forgot to add yourself to the sysadmin role when installing SQL Server. If you are a local administrator on your machine, this blog post can help you use SQLCMD to get your account into the SQL Server sysadmin group without having to reinstall. It's a bit of a security hole in SQL Server, if you ask me, but it'll help you out in this case.