Below is a link to another post that has the fix in it.
https://www-secure.symantec.com/connect/forums/excluding-items-installed-software-report-0
but basically its this:
I would recommend cloning the current Installed Software report by right clicking on it and selecting Clone.
Once you have a clone you can edit it and change the SQL inside the report to remove the unwanted named software. You do this by opening the report and at the top right is an edit button.
Once you have clicked that you will see a Parameterised Query tab under the Data Source tab.
There are 2 sections based on Managed Software and All Software you will need to edit both sections to remove your core software from the report.
I would add a line like this below the first line of each sections where
AND (LOWER (sp.Name) NOT LIKE '%.net framework%' OR LOWER (sp.Name) NOT LIKE '%flash player%')
There where sections should look abit like this:
WHERE LOWER (sp.Name) LIKE LOWER ('%Name%')
AND (LOWER (sp.Name) NOT LIKE '%.net framework%' OR LOWER (sp.Name) NOT LIKE '%flash player%')
AND (LOWER (isc.Version) LIKE LOWER ('%Version%') OR '%Version%' = '%')
AND (LOWER (vc.Name) LIKE LOWER ('%Company%')
OR '%Company%' = '%')
AND sp.[CreatedDate] >= '%Discovered since%'
and
WHERE LOWER (sc.Name) LIKE LOWER ('%Name%')
AND (LOWER (sc.Name) NOT LIKE '%.net framework%' OR LOWER (sc.Name) NOT LIKE '%flash player%')
AND (LOWER (isc.Version) LIKE LOWER ('%Version%') OR '%Version%' = '%')
AND (LOWER (vc.Name) LIKE LOWER ('%Company%')
OR '%Company%' = '%')
AND sc.[CreatedDate] >= '%Discovered since%'