CREATE TABLE #test (
fullname VARCHAR(20)
)

INSERT INTO [#test] 
SELECT 'RobertJain' UNION ALL 
SELECT 'JansonStuart' UNION ALL 
SELECT 'IsmailSummit' UNION ALL 
SELECT 'JohnAbharaham'

SELECT [fullname],
LEFT([fullname], PATINDEX ('%[A-Z]%', SUBSTRING([fullname], 2, 1000) COLLATE Latin1_General_BIN)) AS FirstName,
SUBSTRING(fullname, PATINDEX ('%[A-Z]%', SUBSTRING([fullname], 2, 1000) COLLATE Latin1_General_BIN)+1, 1000) AS LastName
FROM [#test]

DROP TABLE [#test]