I wondered whether someone would even bother making a USB-to-serial adapter driver for Windows 7. After I dropped the one and only laptop that hasn't given me problems last night and destroyed the display, I really wanted an answer to the Windows 7/serial port question. I found this link for a CoolGear USB-to-serial adapter that does have a driver for Windows 7. I have used CoolGear adapters before, and they have worked great. There's a nice demo on the installation/setup on the following link:
http://www.usb-serial-adapter.com/index.html