I have a semi-custom built PC that has a well-used 500GB Hitachi HDD in it with my trusty Windows 7 on it. I was doing a full clean of the computer so I disconnected the hard disk and cleaned the case.
Then I put it back together and tried to turn it on. The BIOS screen flashed by successfully, but then it said that although it recognized the disk, there was no boot device on it. The hard disk, incidentally, never went near any magnets while out.
I also tried to use the boot menu to get it up and running, but the same exact thing happened. I tried it again with a different hard disk (Windows 7 again, but in a tiny 160GB disk) and it ran just fine. I even used the same SATA and power cords!
I'm not near my computer now, so I can't say the exact model and info. But for the record, there was no audible clicking, and it vrooomed normally when I turned on the PC with just the power cord connected to the HDD.