With the command below you can easily create a new windows eventlog. The command creates an informational event in the specified source; automatically creating the source if it does not exist.

EventCreate /L Application /T Information /ID 900 /SO "Your.Eventlog" /D "With a description"

/L The eventlog to create an event inEvent
/T Information
/ID The event ID for the event
/SO The source for the event
/D is description