Computer is usually set to default boot drive to DVD/CD rom, if it's the case then it will seek a the DVD/CD first before booting up on HD, now if your DVD/CD rom has disc on it, it will read the disc first, that explains the vibration when the disc is rotating making a noise. If you would like to set the first boot device to HD? you have to configure it through the CMOS set-up.
How to enter the BIOS or CMOS setup.
Because of the wide variety of computer manufacturers and BIOS manufacturers over the evolution of computers, there have been numerous different ways to enter the BIOS or CMOS Setup. Below is a listing of the majority of these methods as well as other recommendations for entering the BIOS setup.
Notice: If you are unable to get into the BIOS or CMOS setup because of a password contact your system administrator or the one that sets up your PC.
Thankfully, computers that have been manufactured in the last few years will allow you to enter the CMOS by pressing one of the below five keys during the boot. Usually it's one of the first three.
Then you will see something like this, set your first boot device to Hard Disk.