DB Engine :: Server Change Name

I have a problem upgrading a McAfee ePolicy Orchestrator which uses SQL Server 2008 R2 SP2. McAfee logs indicate that server names from SQL server and from McAfee installer does not match.It seems that the reason is that machine name was changed after SQL Server was installed.

MSDN instructions for sql server name changing give next commands to solve this problem:
SELECT @@SERVERNAME AS 'Server Name';
sp_dropserver <old_nameinstancename>;
GO
sp_addserver <new_nameinstancename>, local;
GO

But it didn't work for me, because "SELECT @@SERVERNAME AS 'Server Name'" shows correct (actual) name of sql server. So sp_dropserver says that there is now such instance.In the same time if I use this commands:

select serverproperty('MachineName')
select serverproperty('ServerName')

I get old (not actual) name.

epo-server is an actual computer name WIN-VUN5TSKAHG1 is an old name.