Neither of the first two videos are about manipulating voting ballot marker macines or scanner/tabulator machines. Coomer is clearly referring to the main county windows server that the election reporting software runs on. The administrator of the server can indeed access and change any file on the server. More to the point, there is an audit trail consisting of paper ballots and a paper print out of the results for each voting scanner/tabulator machine.
The last article by Snopes confirms the accusation is unconfirmed and this is what the defamation law suit is all about. Hand counts/audtis have confirmed the there was no manipulation