At least once a day or more my explorer.exe crashes with the error "Data Execution Prevention - To help protect your computer, Windows has closed this program. Windows Explorer [Close Message]"
explorer appears to continue running until you press the close message button, at which time explorer stops running (you can see the taskbar and desktop disappear) and then it automatically restarts itself (explorer.exe I mean, not the whole PC) and the taskbar and desktop come back.
It does this at random times. Although there is a slight bit of a trend: it seems to do it after you're finished doing something, so for example, you just moved a bunch of files around and then you closed windows explorer. Or when you close steam. Or when you click on the safely remove hardware icon in the system tray (it only did that once, every other time it doesn't). Other times it happens after you haven't been doing anything for a few moments (for example 7 seconds after exiting something).
Event Viewer says: "Faulting application explorer.exe, version 6.0.2900.5512, faulting module unknown, version 0.0.0.0, fault address 0x038e33ec."
A couple few years ago I got this PC with windows XP already installed on it (it was previously used in an office, and it appeared their IT department had formatted and reinstalled windows before selling me the machine) so I just went with it, I didn't format it again since I don't have the XP disc (but I do have legit XP, the PC has the key certificate sticker on it etc).
It has been doing this data execution prevention behaviour the entire time since I got it. I've cleaned the pc many times, it's completely clean and I know about every exe and service that runs on it. Recently I got a new motherboard (not to fix this) and it still does the same error.