Mysterious 'Whirring' noise.

[MurderousMincePie]

So awhile ago I put together a PC and it works fine. Except every so often when I start it up it makes a very loud 'whirring' sound as if the fans are catching on something. Except there not, I've checked multiple times. None of the fans are catching anything. This morning it did it again and it didn't stop until I unplugged the DVD drive. However it is possible that it was not the DVD drive and it's something else that is causing it. So is it even possible for a DVD drive to make such a loud noise even when no disc is inside of it and it still reads discs? The DVD drive is the oldest component by far and was taken from my old machine.

 

[turbopiki]

From which part of PC is the noise coming from ?

 

[Vic 40]

Is the dvd drive still set as primary boot device? Maybe set hdd as first in that case.