I had the exact same problem about a year ago. Poser 4 ran fine on my laptop computer and then all of a sudden while working on a very intense project the computer would restart for no reason. I did some experimenting and found that after upgrading my BIOS (via software patch), the problem went away and never happened again.

Poser 2, 3, 4, 5, 6, 7, 8, 9, 10, Pro 2014, 11, 11 Pro