EXECUTE sp_helpserver
The instances will be available as [name]. I'd suggest tabulating them like this (pseudocode):
CREATE TABLE [cpqaAnswers].[cpqa].[tbl_RR_instanceName](
[Idx][int]IDENTITY(1,1),
[iName][nvarchar](256),
[iNtwkName][nvarchar](257),
[iStatus][nvarchar](258),
[iId][int],
[iCollatName][nvarchar](9),
[iConnectTO][int](10),
[iQueryTO][int](11)
)
INSERT INTO [cpqaAnswers].[cpqa].[tbl_RR_instanceName]
EXECUTE sp_helpserver
Then just use a string manipulator (pseudocode):
SELECT [Idx], [iName] FROM [cpqaAnswers].[cpqa].[tbl_RR_instanceName]
Know where the '\' is located by using this (pseudocode in a pseudo step):
CHARINDEX('\',[iName]) -- which'll return an integer "n"
Then do the special query (pseudocode with pseudo variable):
SELECT LEFT([iName],"n") FROM [cpqaAnswers].[cpqa].[tbl_RR_instanceName]
WHERE [Idx] = 1