What PDF Viewers can I use to open PDF files created by Win2PDF?        

Win2PDF creates PDF files that conform to the published PDF file specification.  Any PDF viewer or PDF reader will be able to open, view, or print PDF files created by Win2PDF.

The most common PDF viewer application is the free Adobe Reader software.  This software can be downloaded from Adobe's web site here:

Adobe Reader

There are numerous other 3rd party PDF viewer applications, many of which have smaller downloads and load PDF files quicker than the Adobe Reader software.  Some additional viewers you may wish to try are:

Sumatra PDF Reader

Evince for Windows