Epic fail for storing unencrypted passwords in the database! You should store a hashed password in the database. Your application should then create a hash during the login and query the database using the hash. The query will return a record only if the hash matches the hashed password stored in the database.
Assuming that your hash will contain both upper and lower case characters, you can use the following query to do a case-sensitive compare:
select * from User_Groups
where UserID = 'VINOD'
and [Password] collate Latin1_General_CS_AI = @hashedPassword collate Latin1_General_CS_AI
You should use a different collation name if your data will contain Unicode or non-Latin characters.