Can you download books to a nook from a PC or do you have to have a wireless router?

Yes, you can download books to a Nook from a PC without needing a wireless router. You can connect your Nook to your computer using a USB cable, transfer the eBook files directly to the device, and then access them on your Nook. Additionally, if you have a wireless connection, you can also download books directly through the Nook's built-in Wi-Fi.