Now known, in Windows 8, affectionately as Frown of Frustration.
Has been occurring over past several weeks. I've had 8.1 up and running for about 2 months now. Been putting on a multitude of new programs and devices, so it's very difficult to establish what the conflicts are. However, using WinDbg, as well as witnessing several crashes first hand, I'm able to see that most/all are with "bdfndisf6.sys". I've uninstalled/reinstalled Bitdefender with no resolution. If I uninstall and leave it off, all is well.
I'm guessing I'm not the only one out there who has encountered this. Is there a work around/solution/fix that I might employ?