Thom,
Unfortunately, you're dealing with Windows, so my advice will be of limited value. To get your VST instruments to jive with your DAW (providing Windows is not interfering), the information would best be solicited from Presonus - the VST software packages will be fine, but how Presonus manages them will be what you need to clarify.
Once you have your first VSTi situated, the rest will probably be easy to deploy successfully...