These both appear to be OS errors, as the corresponding errors in SQL Server have messages that don't seem to apply. I will assume that when you get the error 193 from the mssqlserver service, it fails to execute. If this is true, that is probably why SQL agent won't run. It is dependent on mssqlserver, and cannot run if mssqlserver is not running. Is this a new installation? If so, I'd suggest that you simply reinstall. If not, you may want to research the error 193. Find out what's causing that and fix it, and your agent should start working. Because these seem to be Operating System errors, you may have better luck researching at a Windows site/forum.