Poser 6 should work fine if you install it in a different location other than Program Files.  I have P7 working on a Win 8.1 PC. No problems.  

Library issues, is your Library loading with the content folders open?  This can potentially crash Poser if you have fairly large runtimes.  

Update to the most current SR as posted.  

Unless you have Adobe updates blocked, those updates will should automatically popup whenever Poser Pro is accessed.  There are no version selections, as Vilters mentioned.

Now for the fun part, describe where PP and your content is located.  Old time, conventional install no longer applies with Window versions Vista and up.  You must select an alternate installation when installing your software otherwise, you will have major problems just accessing the app.  The more info you can provide, the better.  I have PP2014 running on Win 8.1; I have minor glitches but the software is fully functional when in use.