* T-SQL Query to find list of Instances Installed on a machine

DECLARE @GetInstances TABLE 
( Value nvarchar(100), 
 InstanceNames nvarchar(100), 
 Data nvarchar(100))  
Insert into @GetInstances 
EXECUTE xp_regread 
  @rootkey = 'HKEY_LOCAL_MACHINE', 
  @key = 'SOFTWARE\Microsoft\Microsoft SQL Server', 
  @value_name = 'InstalledInstances' 
 
Select InstanceNames from @GetInstances