Heat problem is a new angle, worth adding to my list... but it can happen after only a very short while.. that's the most frustrating aspect.. there is no real pattern to it. The only pattern is it will happen, when can vary... 2 mins, 10 mins, 30 mins.. I know poser crashes for all sorts of reasons but this is too regular to be acceptable... I reinstalled P3 out of curiosity... I wondered if it would instigate the same problem... surprisingly and annoyingly it did! I wouldn't think they interfere, they are on different directories, anyway I only had P4 installed at first..one reason I upgraded to P5 was to see if it cured the problem and was most annoyed when it went after just 10 mins!!! after I installed the SR4 to P5 it ran for nearly an hour, thought I had cured it..then it went! rebooted opened P5 again and it went again after 5 mins!.. tried later and it went after 15 mins.. see what I mean! unfortunatley while the shop that built the pc is familiar with PC's in general they have no experience with poser...