Can you verify Driver Verifier was active at the time of any of these crashes? I'm checking them and I don't see it turned on. You can verify by opening DV again and selecting Display existing settings. If list of drivers is empty, it's off. Remember that after your set up DV you need to press that Finish button and then restart the PC cleanly. It must at least shut down cleanly during the restart process, otherwise the settings are lost. Read through the article on it thoroughly to make sure you're aware of any new behavior caused by having it on, like the common boot loop it causes. Send us crashdumps of any new crashes it produces.