I bought a recent HP pavilion that had Poser 6's recommended specs.

I've added  the Poser 6 cat, dog, horse, raptor, fish, dophin, lion and frog figures.  I've noticed that at this point, Poser 6 will only open the Poser file if I double click on it from the My Computer browser. (When I'm in Poser 6 itself and simply open it, I get the cursor back, but no document screen opens.)

But with the scene open under My Computer, I've added Ben Casual and then everything grinds to a halt.  The parameter dials are sticky and slow.  I don't know if this is normal or not. I tried the various figure display styles, and even hiding the animals.

My thread search on "Poser 6 not opening files" turned up the thread on the evils of having Norton on your machine. My PC came with Norton, so tommorrow is Nuke Norton Day (wish me luck). 

BTW, the thread search could be made a little better.  It pulls up a whole lot of extranenous stuff.  That's one reason people keep asking the same questions.