[Troubleshooting] I just built my first PC, but I'm having PSU troubles

Building went fine; I have repaired computers several times before so building was really just repairing all the parts to one computer. The trouble is, I got a Corsair CX600W from a friend because he could give me a better deal than Newegg and I'm on a tight budget. All the parts seem to work fine, but the PSU fan is rattling like crazy. It rattles much less when unscrew the fan grill, but it still rattles a fair bit. I thought maybe the fan was hitting soemthing so I turned it upside down, and a little rubber screw-shaped thing fell out. I'm guessing this is a sort of shock-absorber that absorbs some of the vibration of the fan, keeping it from rattling. Does this seem right to you guys?

Youtube link

If so, I will probably have to send it in to Corsair to repair. Which will suck, because I've been saving for this PC for months and I was really excited to get it running finally. Are there retailers who could do it for me using the Corsair warranty?

Thanks guys