Windows 8.1 becomes unresponsive

After an hour or so of normal, or even no use, windows 8.1 becomes unresponsive. I can move the mouse around, but when I click on something, it hangs and the a few minutes later frees up, the freezes again. When I boot into safe mode I don't have the problem. I have done multiple scans with various software, and with Microsoft diagnoses software. All have found and fixed errors, but didn't fix the problem. My hard drive activity shows maxed out constantly once the problem starts, but not much data being transfered. Anyone have any ideas?

HDD sleep + slow spool up is my guess.

Have you checked event viewer? Check the application logs if you haven't.

Sounds like hard drive I had a small ssd that would do that and occasionally would drop from bios detection. Replaced with new drive problem solved

I would think if it was a HDD issue it would do it in safe mode also. I will look at the logs when I get back home.

I had this exact same issue last night. I installed the latest 19 critical updates and it immediately started doing this same thing.

What I had to do, is boot into win 8.1 safe mode and uninstall the latest critical updates.
And, like you, it runs just fine in safe mode.
I am not sure which one it was, and in order to figure it out I would have to install each critical update one by one until this issue happens.

I am currently running ClassicShell and Win8 gadgets. These are the only two third party system apps I am running.