I found a couple support threads that had indicated it could be caused by a windows update. Can you roll back to a previous point before any updates on 8.1?

There's only a couple of things I can think of that can cause the memory leak you're seeing:

1.) A Windows update has caused some kind of corruption that's allowing the .exe to allocate memory it shouldn't and not freeing up the memory when it isn't needed. You can try to roll back to a previous restore to test this one.

2.) A file your registry is corrupted and is letting the .exe run amok eating up memory until there is none left crashing the app in a kernel panic. Try to use a reg cleaner to see if it cleans up the issue.

Those are the only things that could be the cause that I can think of. I dunno, Windows 8.1 gave me a permissions issue and made FFXIV have problems. I couldn't get 8.1 off and the corruption was so deep that I had to BIOS flash (which flashed bad) where I now have to pick up a new motherboard. I personally don't trust 8.1. It's literally the root of all evil.