you could simply sum the two together as a third column, i'd think:
SELECTComputerName AS 'Computer Name',
SUM(BlackWhiteTotalCount) AS 'Total B&W Pages',
SUM(FullColorTotalCount) AS 'Total Color Pages',
SUM(BlackWhiteTotalCount) + SUM(FullColorTotalCount) AS 'Total of All Pages',
Name AS 'Printer Name'
FROM [dbo].[db_name]
WHERE ComputerName LIKE 'ComputerName%' --There are 2 computer names that I'm looking at
GROUP BY ComputerName, Name
Lowell