Apologies in advance if you've tried this already or it's stating the obvious, but when I tried to get my printer (an old Laserjet 3200) working in Windows 7, it wasn't there either. I did all sorts of digging into old drivers, screwy workarounds, etc. until I finally came across a post somewhere that said something like "Uh, why don't you just click on the "Windows Update" button in the add printer dialog?"
So I did, waited a minute or two for it to populate and, voila, there it was. Felt like an idiot, but it worked.
Start, Devices and printers, Add a printer, Add a local printer, Use an existing port, click on Windows Update, wait a minute, then check the list again.