The GPL (and AGPL) do place some restrictions on how you can integrate it into another application but this doesn’t have anything to do with commercial use.
Basically, if you create a derivative work and publish/sell it, you also need to license it under the AGPL. In case of the AGPL it also applied if you use it to offer a service. But if you only use the unmodified version (same source code) and the intended application interfaces, this does not apply.
Running the application on Windows is clearly allowed. The second case also sounds ok (allowing this is kinda the point of FOSS). However, if you create an improved version of PDFCreater, then you’ll need to publish it under the same AGPL license.