Interesting that you ask that question in a post with a link that is selling consulting services that should answer the question.
The Pactor modem
could care less about the operating system. You have two issues: 1. appropriate drivers (see the SCS web site) for either a PTC-IIusb or appropriate drivers for whatever serial-USB converter you use with a PTC-IIpro and 2. compatibility with whatever client software
you use (often Airmail) for e-mail over HF radio
. Airmail works fine on Windows 7 using the same configurations that work on Vista.