Windows 7: Periodic error: Programs freeze and harddrive LED is constantly on

I'm having a truely annoying issue. I cannot figure out why.
All of a sudden, maybe every 10-30 minutes, the harddrive LED will go on constant light, and the computer will come to a halt.
It doesn't exactly freeze. I can still move the mouse, and do some minor tasks.

I'm running windows 7 Ulti x64 on it. It is my media center, hooked up to the TV through HDMI.
CPU is Intel I3-2100T and the motherboard is a Intel Desktop Board DH67CF.
It is running a WD Green disc.

It has been running, without any issues, for about three months now. Then a few days ago, all of a sudden, it started doing this.



No new updates were put on, or any new software.
I got home from work, and it wouldn't start. It locked up at "Starting Windows".
So I put the Windows CD in, and went into repair. It fixed some "Disc errors" and it was able to run again, but now with this stupid issue.

I have been unable to isolate what is going on. No CPU or mem usage looks strange or spikes when it happens. I have watched resource manager, but have not been able to see what is using the disc.

I hope you guys have some ideas.
Thanks.

Run the system file checker to see if anything crops up.

SFC /SCANNOW : Run in Command Prompt at Boot

You may also want to run a full anti-virus check, for which Malwarebytes is highly recommended.

http://www.malwarebytes.org/products/malwarebytes_free

I did do a sfc /scannow, and it found nothing.
After my post, last night, I decided to install all the updates that were available, hoping they would fix it.
But instead I am now back to, not being able to boot.
I'll do a final attempt, after work today, with the windows disc. If it doesn't work, i'm very tempted to simply reinstall.
Atleast then I will know if it is driver or hardware.

I bet the harddrive is broken, now that they suddenly cost a ton.

In that case, a repair install will be your best option.

Repair Install

Please keep us posted as to how you get on.