DELL POWER EDGE R 720 Server - No on screen messages while bootup sequence

Hi,

 I own a dell service class machine as mentioned in the subject. In general , the system will display the boot sequence messages during when we turn on the machine right. Like DELL logo followed by hard disk, memory details and network card/ Other hardware details etc. 

 But my machine is not showing any such on screen messages while booting. It stays blank till the time the desktop loads. What could be the exact cause and solution for this problem? Because of this, we are not able to choose the boot options or anything during boot up. Hoping for a solution to this case. 

Thanks in Advance. 

Siva