Constant hard disk activity

indexing?

Possibly. I don't really know what to look for in this respect but I opened the indexing app and couldn't see anything relating to this drive (I) in the list. It's all geared towards the C: drive. I think what I will do tomorrow evening is boot the machine up and leave it do its thing for a few hours and hopefully it'll die down

Hmmm, I'm not even convinced it is the hard drive now. It does sound like the feint whirring of a hard disk writing to disk. But I listened carefully to actual HD activity when it reads and writes and it's much louder and more distinctive. So the feint whirring is something else. Could be anything I suppose. As the system is working absolutely fine and seems nice and cool I'll try and put it to the back of my mind. from sitting position at desk it can barely be heard unless the house is very quiet (which is rare)

That sounds like a fan, not a HDD.
They make more noise when the bearings get worn, initially it can be intermittent and at a low level.
Later on it will get noisier, and eventually seize up.

Obviously you need to replace that fan. You may get a temporary fix by oiling the bearing.

You should have an LED on your case for hard drive activity. If that isn't lit or flickering quickly, it definitely isn't the hard drive.

DeaconFrost said:

You should have an LED on your case for hard drive activity. If that isn't lit or flickering quickly, it definitely isn't the hard drive.

You'd think there should be an LED for disk activity but as expensive and flashy as the case is (Coolermaster CM Stormtrooper) I don't think there any! Not that I can see round the front of the case too well anyway. I wouldn't buy it again as the case is unfeasibly large and since my wife made me move the pc into a small area everything is no longer that easy to get to. But as disk usage and resource monitor report little or no activity I guess it cannot be.

The photos of the case seem to show one near the power button, but I see no mention of it either way in the manual.

There aren't any that I can see. The case is full of flashy fan related buttons at the top and lighted grills but hard disk LEDs are conspicuous by their absence. I have had my ear against the case several times this evening. My wife thinks I am going mad! I am convinced it is the hard disk despite no usage showing in task monitor. It's been whirring away quite a bit but then suddenly stopped after I left the computer idle for a while. But then back to whirring as soon as I briefly opened steam and shut it down (no updates going on), it then persisted with its whirring for a good ten minutes more before going deathly quiet. So god knows what it is doing.