When system is powering on, it will beep. Only you heard beep, it can prove system is on successfully.

But if system is beeping frequently while it is not rebooting, maybe you set up beep in alarm mode.

Go to Main Menu--Alarm--Motion Detect/Video Blind/Video Loss/Abnormality to uncheck buzzer for every channel.

In Motion Detect

In Video Blind

In Video Loss

In Abnormality

If the system will reboot on every Tuesday 1 am and it will cause a beep, please disable auto reboot if you don't want it. 

Go to Main Menu---Advanced---Automatain.