Try this:
SELECT Manufacturer, [Product Name], amms.[Product Version] AS [Version],
acid.Name AS [Computer Name], acid.Domain AS [Computer Domain],
SUM([Run Count]) AS [# of Uses], MAX(amms.[Last Start]) AS [Last Start] , acid._ResourceGuid
FROM Inv_AeX_AM_Monthly_Summary amms
JOIN Inv_AeX_AC_Identification acid
ON amms._ResourceGuid = acid._ResourceGuid
JOIN CollectionMembership cm
ON acid._resourceGuid = cm.ResourceGuid
AND cm.CollectionGuid = '%_Collection%'
WHERE amms.[Product Name] LIKE '%' + '%_AppName%' + '%'
GROUP BY Manufacturer, [Product Name], acid.Name, acid.Domain,
amms.[Product Version], acid._ResourceGuid
ORDER BY [# of Uses] DESC, [Name] ASC
You will need to create a new parameter named _Collection which has a Parameter Type of "Item Picker" and a class filter of "Collections", and another called "_AppName" which is a Basic parameter, with a "String" type.