novaPDF is compatible with the 32/64-bits versions Windows 8/8.1, Windows 7/Vista/XP SP3 and Windows Server 2012/2008/2003.
During installation the setup will allow you to choose which edition to test. If you're not sure which edition is right for you, you can see a feature comparison here: Compare Products.
There is a 30 day evaluation period during which you have all the functionality of the installed edition but each page of the resulting PDF will show a footer notice. After 30 days, the program will no longer operate on your system, unless you purchase a license and register it. The licensed version doesn't expire and doesn't add any footer notices.
novaPDF requires the .NET framework to work so you'll be prompted during setup to install if it's not already on your PC.