Hi

I think your first problem maybe related to the fact that when your DBA left your sys admins probably disabled or deleted his windows account...which is usually the case...I don;t have enough detail to be sure but with regard to your first problem check all the jobs to ensure that they are not owned by or running under the context of your DBA's old windows domain account...this maybe the cause of your problem

Your second question, i think maybe to do with some third party monitoring tool, from memory, which is not always the best i think IDERA uses a database with that name...Do you still use IDERA or a monitoring tool of osomekind?...It could be that the job was setup to groom idera which i believe, although i'm 100% sure, removes uneccessary/old/redeundant data from the database... If the db no longer exists becuase you have stopped using iDERA but the job is still running it will fail because it can't connect to the database...

Not sure if this is helpful but hopefully provides a place to start

cheers