backup and restore options incase system crached

Hi,

I have 1 DB Server and 1 SharePoint Server (APP + WFE). I have 1 Full Farm Backup and 1 Differential Backup. Please guide me steps to follow in-case of server failure under following senario.

Scenario 1: SharePoint Server (APP + WFE)  Crashed , Database server intact
What step i have to follow in order to restore my SharePoint. 

Scenario 2 : Database server crashed , SharePoint Server (APP + WFE) intact
What step i have to follow in order to restore my Sharepoint. 

Please also give recommendation.

Thanks

iffi