messed up fan?

I was just using my computer for nothing intense just web browsing and I heard the fan in my PC throtoling so i opened everest and it reported normal temps and fanspeeds, so i wanted to see what was causing the noise, I gently turned my PC on it's side and it made a horrible grinding noise, freaked me out so bad, I shut it off manually and opened it, all the fans were in palce but it was off so ic ouldn't see what was going on. I put the panel back on and set it upright and it is running fine and making just the normal amount of noise, normal temps. but DAMN this freaked me out. at least i am on the 1 yr hp warranty if my hdd explodes or something.

 

Prolly just a fan hitting a wire or somthing..... or just vibrating.. My cpu fan im using now is like that. It runs great when on its side.. but ya put it face up .... makes one hell of a noise....

 

I hope thats all it is, couldn't have been the hdd or I probably wouldn't be on my computer on MGs right now.