You can quickly enable or disable alerts from the task pane instead of configuring them in the Configure Alert Categories dialog box.
See Configuring alert category properties.
To enable or disable an alert from the active alerts pane
On the Active Alerts pane, select the alert that you want to enable or disable.
Under Alert Tasks in the task pane, click Alert category enabled.
The alert will be enabled or disabled, depending on the current setting. The error and attention required alert types cannot be disabled.