I have an HDD that I've been using for a while. It's a Samsung HD753LJ 750GB running on SATA.
According to CrystalDiskInfo it has a Power On Count of 5,174 and Power On Hours of 17,664. Not sure if that would be considered "old".
The problem is, sometimes when I've left the disk idle for a while, it will take an inordinately long time to respond, say a minute or more, and it hangs Explorer in the meantime. However, CrystalDiskInfo tells me that its spin-up time is nothing to worry about. The normalised value it gives is 75, and the raw value is 0x2080.
This problem has just cropped up since I've transferred it to a different system with a fresh install of Windows 7. One thing that I've done differently this time is I've enabled AHCI in the motherboard. Prior to this I'm pretty sure I've been operating off older legacy drivers.
Another thing to note is that I think the problem has improved slightly now that I've installed all updates on the system. Prior to installing the system updates it was constantly happening, but now it's only happening every now and then. It's still too often, though.
EDIT: I've just double-checked, and I've swapped the SATA cable and SATA ports, and the problem still exists.