We really need more information to go on. How about system specs, when it happens etc..?
Judging by the dump files, looks like nvapu.sys is to blame. nvapu.sys is part of nVidia's nForce drivers. More specifically, for nForce audio.
I'd recommend booting into safe mode and uninstalling your nForce drivers. Then install the latest version from nVidia... Providing this information is accurate. That's the best I can do for you without more info, so hopefully it works.