Grinding Noise When Booting Up

Last night, I opened up my case to adjust some screws, because my hard drive cage was making vibration noises. Once I fixed the screws and closed the case back up, I noticed that the vibration noises were gone, but my computer is now making a grinding noise every time it starts up. I have a fairly new computer, and the hard drive I was working on is a Western Digital 1TB Green Drive that I use for data storage. The grinding noise occurs in 2-3 second bursts over a period of about 30 seconds as I'm booting up and logging in. After that, the noise stops altogether. I can also access the data on the hard drive without problems.

I ran the tool and did a quick test on the 1TB drive, and it passed. I'm starting to think it's been making these noises all along, and I just haven't noticed them until now because the vibrations were blocking them out.

The thing is, the noise only happens when my computer is booting up, and it doesn't happen again afterwards.

This is what I think is most likely going on. I just purchased and installed the drive two days ago, and I can still access all the data on it. I found that the vibration noises were a result of improper screw placement. I had accidentally swapped the positions of one of the hard drive mounting screws and the screw used to secure the hard drive enclosure to the wall of the case. When this was corrected, the vibration noise stopped, and must have allowed the seek noise to become audible.