Graphics drivers won't have any effect on your rendering performance because yes that's all CPU in poser 2014, but your graphics card drivers are how *everytthing* gets from your computer to your screen.  It's a cheap and easy thing to test.  But really, when you get this behavior where a program simply "goes away"...no real errors, no real weird behavior before that- it just vanishes, it's a memory addressing issue.  Could be your physical RAM, could be the memory on the video card, could be hardware on the motherboard that sits between the memory and the rest of the system.  Could be driver issues or even a windows update.  Unfortunately, memory issues can be maddening to try and track down.