Why won't the cpu fan brackets screw in?

[jismalin]

Hi,

I'm currently in the process of upgrading my cpu fan and I accidentally unscrewed the fan brackets, and now it won't screw back in. I don't get why, it's the exact same screws and everything and I need to screw it in so i can install my fan. Any suggestions?

Thanks

 

[SpyderTracks]

Is this a PCS machine? Can you post your full specs from the order page?