Computer making strange noises

[Gorack]

Hello, recently my computer has started making strange noises on startup. They sound almost like quacking and im not sure whats causing them. I will try to get a video of the sounds up but right now i dont have a camera with me. Does anybody know whats causing these noises?

[Fuzzykins]

It's either a fan or your HDD on spinup. Open your case and watch when you start it, for any irregularities.