Database Busy, Whats Going On?

Hi, I'm new to c# and sql2005 express. I'm getting an error on the simplest of activities. From C#, i create a database, create a table, then try to delete the database and get a database busy error. I think its because sql has some connections to the database its not releasing. I have already tried closing the connection, disposing of the object and forcing garbage collection for the c# app to no avail.

can someone explain to me wat is going on?

Here is the only function i am calling for c#. I pass in T-SQL command strings such as 'Ceate Database myDB','Create Table myTbl','Drop Database myDB', etc.. :

private bool ExecuteSQLNonQry(string sqlStr)
{
SqlConnection myConn = new SqlConnection(ConnectionString);
SqlCommand SqlCmd = new SqlCommand(sqlStr, myConn);

try
{
myConn.Open();
SqlCmd.ExecuteNonQuery();
myConn.Close();
return true;
}
catch(Exception e)
{
MessageBox.Show(e.Message.ToString());
return false;
}
}