yup, video drivers are likely to be the culprit, i updated to the latest full release for my GT430 a couple of months back, and deleteing bones, moving from set-up back to pose room resulted in CTD on ALL versions of Poser i have installed ( P7, P8, PP2010 and PP2012)

went to the nVidia site and grabbed the latest beta one ( at the time) , worked flawlessly after installing.