Who among the following lives at the topmost floor? 

By using the given conditions, Y lives in an even numbered floor but above 4th floor. From this there can be two possible cases. Case-1: Y lives on 6th floor and Case-2: Y lives on 8^th floor. P likes Asus and lives on an odd numbered floor. P doesn’t live at the lowermost floor and at the floor just below or above Y. In case-1, P lives on 3rd floor and in case-2, P lives either on 5th floor or on 3rd floor. Four people lives between the one who likes Asus and the one who likes Acer. From this it is clear that P lives on 3rd floor. The one who likes Apple lives immediate below the floor on which the one who likes Acer lives. Two people live between Z and the one who likes Apple.  Z doesn’t like Dell and Sony. From this case-2 will be eliminated. Further C likes Lenovo and lives at one of the floor above O. So, C can live on 5th floor only. S likes Microsoft. So, S lives on ground floor and O lives on 2nd floor. The person who likes Sony and HP doesn’t live at the lowermost floor. So, Y likes Sony. W does not like Apple. So, Z likes HP and Q lives on 7th floor. So, the final arrangement is---