Computer locks when playing video files

My computer sometimes, every 1-3 months locks up when i open or close a video files, maybe sometimes even when i am just viewing folder with lots of videos (thumbnails). i5 2500k, R9 390, windows 8.1. Hardware stress tested in very rigorous way, no problems found whatsoever. Using klite codec pack with media player classic. I remember that very often the computer locked when i had video running and i clicked on it and tried to move it. Sometimes i remember when opening a video and moving the mouse cursor that would also trigger a freeze. Sometimes when i open a video and move mouse at the same time, the mouse will lag very badly for like 2-3 seconds, even though the very same video will not do that 99.999999% of time, none of the videos will. I even had my eye on my GPU because that is basicaly the only thing i can think of. Like, i know that when i click on a video, gpu and gpu mem clock will rise. So my hypothesis was that occasionaly something goes wrong in this switch. But i have no way to prove it. I just spent 20 minutes clicking on the same 2 movies i did during last crash but sadly i cant get anything to go wrong. None do i know where any logs are that would help me or how to schedule them (GPU, GPU drivers, MPC, LAV, itd.)

It happens with various video types, since i have probably all of them, it happened with every single 1 of them. The latest happened about an hour ago so about this one i actualy have some data to write down (for others i dont, i forgot them). So i will write this event down but make notes where i think necesary. I did notice 2 things in event viewer, i managed to solve the first one, the second one remains:

1. A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 10. The Windows SChannel error state is 10.
I seem to get rid of this by enabling all SSL and TLS in internet advanced options.

2. Engine Glitch: CP Server Input Endpoint - Starvation: pCCrossProcessServerInputEndpoint=[0x2375750770] WriteOffset=[4196] ReadOffset=[3812] BufferSize=[2648] BytesAvail=[496]
Not sure what to do with this. The only thing that comes to mind is USB signal is getting disrupted (i am using USB DAC), i can try changing the port i guess.



EVENT:

1) I was viewing folder with 96 video files in details view. Most files are X265 (handbrake by me), others are X264 (downloaded). I clicked those files a lot in last 2 months, this is the first crash i had with them
2) I opened 2 video files many times and closed them (comparing quality). Then just before the crash happened i had 2 files playing side by side and when i closed 1 of them, mouse disapeared, keyboard didnt respond anymore. I heard music for 30 more minutes and then silence. No BSOD. Nothing in event viewer except message that pc was shut down inproperly

I opened the files again and checked whats running it. Its LAV audio, subtitle and video codec. I am including my settings of MPC here.

SETTINGS SCREENSHOT:

Such lockups/freezes are often related to failing to read data from harddrive (or SSD). Since it appears random and rarely, it probably isn't due to bad sectors on the drive, but a harddrive error scan never hurts.

It is very likely a hardware related issue. Given the low frequency it could even be something externally, such as a power surge/drop that triggers the problem. Or a heat related issue.