Configuring 'New Mail Alert' feature in Outlook Express

The new mail alert in Outlook Express notifies you when a new email message has been received. To enable this feature, follow the steps given below:
Open Outlook Express.
Click on Tools > Options.

The Options window appears
Click General tab.
In the Send/Receive Messages area, select the check box next to Play Sound When New Messages Arrive.
Click Apply.
From now on, you will receive alerts whenever there is a new mail in your Inbox.