Er ... dunno. I didn't "build" my Win 7, I just installed it off the DVD. It "just worked", once it had downloaded all the extra drivers it needed.
... apart from Windows Fax & Scan. I open Fax & Scan, tell it to scan, and it says "You ain't not got no scanner, Mister." Oh yes I piggin' have!
I can import pictures, so scanning the document first and saving as a JPEG works fine.
But then Fax & Scan can't read my Outlook address book, where all the fax numbers etc live, so it's all a bit of a mess, really. I'd have to open Outlook, find the person, copy and paste the fax number, and ...
I've not got as far as trying to see if it then finds the Faxmodem. Life's too short!
I've got this prehistoric bit of software called WinFax that I bought last century.