I've never had any problems with Poser in the background (well, OK, I have run out of memory during some renders, but otherwise...). At home I run Windows 98 (SE, I THINK, but I'm not sure). At work I run on NT 4.5something. Both at 128 MB RAM. 400 mhz proc at work. I USED to run a 266 Celeron at home, but have a 550 PIII now. But then I rarely play games while rendering (if I do, it's something lame like Freecell, or something that uses the CD more than the hard drive, like Civilization II)... I often write or read e-mail during renders though... Usually I have two or three graphics apps open (PaintShop Pro, Poser, sometimes Bryce), a word processor (Word) and America On-line open with no problem...