Cleaned up my statement, the sub query was enough to get the information that I wanted. I think I was originally going somewhere with a query with a subquery but I don't think it is necessary.
SELECT computer_name AS 'Computer Name',software_id AS 'Software ID',softinv.name AS 'Software Name', softinv.version AS 'Version', uninstall_string AS 'Uninstall String'
FROM computer_software csoft
JOIN computers comp ON csoft.computer_id = comp.computer_id
JOIN software_inventory softinv ON csoft.software_id = softinv.software_inventory_id
WHERE computer_name NOT REGEXP '#[0-9][0-9]-'