The blue screen dump indicates that the "Process_HAS_Locked_Pages"
Process has locked pages
is a driver problem. It means that a hardware driver either didn't unlock memory pages that it locked when starting an I/O operation, or that it tried to release pages which were already unlocked. Essentially, leading to a low-level memory "leak" in the driver.
On the page I linked above, Microsoft has instructions for enabling a registry flag that causes Windows to track all locked pages. This should allow you to fairly easily diagnose which driver is causing the leak (when it happens again, the driver should be listed in the bluescreen message).
Don't leave this registry flag enabled once you figure it out, though, as it has performance implications.
My guess is either sound device drivers or video card drivers, but it could be any of a whole swath of things.
PS. I should add... It can also be caused by a hardware problem, most likely bad RAM. If you just added new RAM, or you've seen other random instabilities, it might be worth checking that. Or, if when you enable the flag above, you see a variety of different hardware devices causing the issue, it could be bad RAM or a failing memory controller (typically on the CPU die anymore, unless it is an old CPU).