On one of my servers I can select Event ID "Disk - 7" to notify me of a hard drive with a bad block. However, on all my other servers, I do not have that Event ID option.
If you are referring to the popup generated by the Add Event Filter button under Configuration/Reports & Alerts/Email Alerts: this popup only lists events that have already been scanned.
To create an alert for an event that hasn't been scanned yet, select a random event and modify the alert criteria afterwards. (Hit the pencil shaped edit button next to an alert to modify the alert criteria.)
