I have a home built machine that has been running without issue for a few months. On Friday, out of nowhere my screen completely froze (no change in clock, etc.) without any response to keyboard strokes, mouse clicks, CTRL+ALT+DEL, and so on. Some applications were running but I wasn't using the keyboard/mouse at the time of the lock up. I then did a hard reboot, and everything ran fine for a few hours when another freeze occurred - again, nothing in event log to indicate what occurred before the freeze.
I began going through some troubleshooting like SFC scan and wasn't really finding anything until I noticed that my Windows Experience Score needed to be refreshed b/c new hardware had been detected (it may have been this way for a long time, I'm never in the control panel during my normal usage). Anyhow, just for the heck of it I decided to click the button to refresh my score. The update began to progress normally "Running the Direct3D..." then "Running the ...." and so forth until it got to "Tuning Windows Media Decoding" at which point it froze. I assumed that it was just time for another random freeze, but after hard rebooting and attempting to refresh the Windows Experience Score again it froze at the same point in the update "Tuning Windows Media Decoding". I verified that it was reproducible this way 4 times.
So I guess my question is, what occurs during this update either at or immediately after the "Tuning Windows Media Decoding" that could cause a lock up? Is it accessing a certain driver at that point in time?
Clearly, I don't know enough to identify the issue myself, but I'm guessing that my ability to reproduce the issue is a good thing. Would greatly appreciate any help in trying to pin down and fix the underlying cause for these random lock ups. If there is any additional information that I could provide which would be helpful, please let me know.