If you had Windows 8.1/10, you could use the Nook App from the Microsoft App store, but with Windows 7, you can try to use the unsupported
Windows Nook app or download the Nook Study app from one of the sites that has an archive. I find that I have to log out of the Nook app, log back in, and refresh a bunch of times to get the Windows Nook app to notice new ebooks.