Windows 7 hard drive thrashing regardless of system being idle or in use

I can hear my C hard drive thrashing away when my system is idle, and even when my system is running programs.

Thought it might be Firefox that's using the hard drive a lot - checked it out, uses the hd a bit but no more than usual, but I can still hear the hard drive clicking away. So I close Firefox. Still going.

Tried switching browsers to Chrome, and even that doesnt have an awful lot more disk usage per cycle than Firefox did. But regardless of whether Chrome was open or not, I continue to hear the hard drive thrashing.

Tried using IE as my main browser, still thrashing. (But IE has the least disk usage out of the 3 main browsers I found - I can still hear it thrashing though )

I checked out Windows Task Manager, but none of the processes shows heaps of disk usage. I then tried Resource Monitor and 'System' with PID 4 appears at the top of the list of processes sorted by disk usage. But there are heaps of sub-thingos (Forgive my jargon ignorance) running under 'System', so which one is causing the disk thrashing?
I disabled Windows Media Network sharing process that has been suggested on the forums, with no change in disk usage.

I remembered a friend of mine mentioning disabling Marvell/other manufacturer's leftover RAID drivers when installing a new PC [Sometimes they're installed along with mobo drivers] (Where the system has no RAID array installed) slowed his disk usage down.

I have no RAID array on my PC either, but noticed a Marvell driver under the 'System' heading when using SysInternals Process Explorer.

I also noticed some other errant drivers, perhaps one of these is causing the disk usage problem?

The whole thrashing business is awfully random - will start and go on for 30 to 40 minutes and then stop for hours, then begin again.

I don't think it's a virus, as I have Avast! and can use the File Shield to monitor what files Avast! is scanning - weirdly, even though I can hear the hard drive in use, Avast! does not pickup/scan any of the files that the disk is supposedly using.

Below are the various screenshots I have uploaded in the hope someone can help me solve this hard drive problem before it wears out and dies a lonely, premature death :P

Stray Marvell Driver.png - Windows Live

Stray AMD Storage Filter Driver.png - Windows Live

Dump Disk Processes 1 3rd Oct.png - Windows Live

I downloaded SysInternals Process Monitor from
Process Monitor

But the program is so much more complex than Process Explorer and I have no idea how to use it.

Can someone please tell me how to run a trace through the events that may help determine which of the running processes analysed in Process Monitor is/are the ones that are causing the high disk usage?

Some More Analysis
Restarted in safe mode (no networking) and went into Resource Monitor (Part of Windows 7) and SysInternals Process Explorer (From Microsoft TechNet) to see if I could isolate the problem.

The entire time I was in safe mode, the hard drive kept on thrashing! :O
I started up Resource Monitor first and saw that 'System' with the PID of 4 was still the most disk-hungry process. Disk usage went from 100KB/sec to 1MB/sec as it did before when logged into Windows 7 normally.

I also saw
svschost (netsvcs),
svchost (secsvcs)
svchost (dcomlaunch)
and other processes like
wmiadap.exe
wmiprvsv.exe appear. The 2 wmi processes disappeared after a short while leaving svchost and 'System' remaining.

I closed Resource Monitor and fired up Process Explorer, and found some weird-looking processes:

Under wmiprvsv.exe there was a file called locale.nls, with no manufacturer name/description (In contrast to other services/sys files which have 'Microsoft Corporation' as their name)

Under each of the svchost.exe processes, out of all the files that had name descriptors (Microsoft Corporation), there were a few without name descriptors that caught my eye:

A file located in Windows/Globalization/Sorting/Sortdefault.nls
A file called locale.nls (Sorry didn't note down the file location)
A file located in Windows/Registration/R00000000000.clb
A file located in Windows/System32/C_28591.nls

All of the above files except for the R000000.clb one were found in svchost, lsass and csrss.

The R00000.clb file was found only in svchost.
I noticed these files because they had no name description next to them - could any of the filesI mentioned be contributing to the disk usage problem?

Hard Drive Thrashing Continues Even After I Logout
I own my own PC and use an administrator account (Not the default 'Administrator' account, but my own account that has admin privileges).

I tried logging out of my regular account and into another limited account I have on the PC. Not only did the hard drive thrashingcontinue while I was logged out and at the Welcome screen,but it continued even after I had logged in to the limited account.

Pretty weird hey?

Weird, yes exactly.
Excellent post, I wish I had something worthy to contribute but my suggestions are pretty mundane and likely considering all the trouble shooting you've already done a bit obsolete.
First, available disk space left? Still plenty I would presume but an important consideration.
Second, TLC (tender loving care) multiple passes with a Defragger, built-in and maybe even a third party Auslogic makes a pretty good one. As well as perhaps a run of chkdsk c: /r reboot and let it finish all five stages.
Third and I have no idea how much memory you have available so therefore no way of knowing how much paging is going on, I would suggest using the advanced tab under performance options and setting your pagefile to zero using the custom size option zero in both boxes and select the set button. Reboot, go back in and reset it to a value of one and one half times the amount of memory you have installed same in both boxes Initial size and Maximum size. If you have a second physical drive (not a second partition) move the swap file off the system drive and put it on the second physical drive.
Fourth, are you sure the thrashing is due to I/Os, do you have any reason to suspect a problem with the actual mechanics of the drive, although I'm not sure how that would account for the fact that the noise is not present for a period of time unless of course there's an intermittent heat issue and the drive spindle and bearings are expanding and contracting.
Just a few ideas and like I said you've probably already been there and done that.