For those that have retired an old PC and no longer have any serial ports, I want to post that I found a USB-to-Serial adapter that works great with the older remotes. It works under Windows 7 and 8, both 32 and 64-bit. Just make sure to force the COM port to either 1 or 2. Didn't even have to use XP Mode!
TRENDnet TU-S9 @ Amazon