sorry I don't have the time to add this myself at the moment.
But basically, DMC4 and other DX10 games have stability problems because of update KB2670838 on windows 7 https://support.microsoft.com/en-us/kb/2670838
It's been mentioned in various forums over time. And after having recent problems with the game crashing in DX10 mode, uninstalling this update fixed the problem for me.
It's important to hide the update in Windows update as well so it doesn't get re-installed. Note that IIRC this removes IE10 as well. And installing IE10 will basically install this alongside it even if it is blocked through WU.
The only thing uninstalling this update has done wrong so far that I have seen is that it messes up hardware accelerated font rendering in Firefox for me. Which is something I have reported to Mozilla in hopes can be fixed. Disabling HWa fixes it for the moment though.