This problem started a couple of weeks ago and seems to be getting progressively worse. Basically I am getting spikes of 100% HDD Usage (with less than 100 KB/s I/O levels) at random intervals while web browsing, word processing, etc. There doesn't appear to be any particular file/program/service that is causing excessive disk usage. It usually lasts between 3-5 minutes during which time PC is horrendously laggy and semi-frozen. Happens about once or twice per hour now. CPU and RAM usage is perfectly normal.
I have scanned the PC with several programs and no malware/viruses were detected. I have not been able to get Chkdsk to run no matter what (command prompt, safe mode, etc). Ran disk defragmenter but did not help. I also tried the PassMark Disk Checkup, but it was not able to complete, said "failure of read element" after 10% complete.
Here's a screenshot I took from my task manager after one of the spikes:
PC is an All-In-One
Windows 7 64-bit
2TB 7200RPM HDD
My wife had similar symptoms once on her laptop; turned out it was the hard drive on its way out (thankfully we were able to get everything we hadn't already backed up off of it, but it was a close call). Obviously I can't guarantee that that is what's happening to you, but your issues running Chkdsk and PassMarkDisk Checkup don't sound like a good omen.
If you haven't already, I'd sincerely recommend you backup everything you want off of that hard drive. Next, I'd recommend you download a free trial of HD Tune Pro (http://www.hdtune.com/). It's what I used to diagnose my wife's failing drive. The general benchmark showed up some odd peaks and troughs, but it was the error scan (with the scan set to its most thorough setting) that showed up the many errors the drive had (the SMART stats also indicated the drive was in trouble).
Again, I can't guarantee that your disk is failing, but it's certainly where I'd focus my attention first if I was you.
Thanks for your reply, I just finished a complete error scan with HD Tune and I got 2 red blocks, both next to each other in the very first row. The other issue of concern is that it found 16 "current pending sectors" and that the temperature is hovering around 53-55 degrees. Everything else tested out OK.
Everything is backed up so no worries there, just hoping I can still get some more life out of this HDD.
55 Degrees, crikey! I guess that's just one of the downsides of an All-In-One, but still, you'd think the manufacturer could of thought ahead a bit more, and designed it with some kind of HDD ventilation! I'm not sure how feasible it is, but if there's anything you can do to cool it down that would be good (probably good to try to tackle this now, before you have to put a replacement HDD in - you don't want that dying quickly).
I'm pleased you have everything backed up, you're a better person than I (I have most things backed up, it's just my weekly backing up isn't, well, it isn't always weekly ). If the hard drive really is on the way out, I really don't know how much time you have left. My wife's one went from okay to horrendous pretty quick (2-3 weeks); it was on it's last legs by the time we got all the remaining data off of it. Still, you sound like you're prepared for the worst, which is definitely the best way to be; any extra life you get out of it is now a bonus.