LinkStation constantly making noise / slow transfer speeds / USB not working

[JaiBones]

All issues now seem to be resolved. I managed to get the 6TB operational again, by deleting all the partitions on a Linux system and then restarting the initialisation process by using the function button on the front of NAS.
At first, I had a solid red light (eek) but I simply powered the NAS down, rebooted, and the initialisation finally worked and I had a fresh, working 6TB HDD ready to set up again.

So;

Issue #1 = Resolved - larger capacity HDDs are noticeably louder
Issue #2 = Resolved - replaced the Ethernet cable
Issue #3 = Resolved - I had USB Device toggled on

Thanks to davo & 1000001101000 for trying to help, I know I've tinkered waaaay too much for all this but I learned a bit along the way, lol!