One thing you could try, if you have your heart set on the "old" environment, is to find a copy of version 6. It's still the one-file-per-table paradigm that version 3 was (albeit with a file format upgrade required). However, it will run on Windows 7. Might get you up and running.
I would still recommend, nevertheless, that you take a stab at upgrading to the current release. Version 6 (much moreso version 3) is very old technology. It's simply not up to snuff by today's security or stability standards, and you'll benefit greatly from learning the new technology. Brains like exercise too.
You could try running a virtual environment (like VMWare Workstation) that runs an earlier version of Windows (e.g. Window XP).
Do you know what is the most recent version of Windows that will be compatible with FileMaker Pro v3?
thanks. i only use it for my invoicing and really want to avoid having to learn the program all over again if i can help it. i've looked around a little for an older version but haven't had much luck.
i've spent a day trying to figure out libre office base. I kind of get it, but can't get it to do exactly what i want....and end up getting a headache after a while.
i've thought about that and may end up going that route.
I was using XP before the W7 laptop and it worked fine.
So many red flags going on here.... ancient unsupported software running on an operating System that Microsoft offiically said it no longer supports. All kinds of security and stability issues. You say you are running your business on this... oh my. So it is something you really rely on. You really need to either bring the software current for security reasons if nothing else, or abandon it. I hate to turn you away from FileMaker, but trying to run a business system on that old of FileMaker software is a really bad idea. FileMaker offers a lot of customization, but if you just need a general invoicing system and don't want to upgrade FileMaker, I would suggest you look at something like Quickbooks or other accounting verticle solution. My preference would be to get you to a current version of FileMaker, but if you won't do that, then you need to find another solution. If you do upgrade to FileMaker 13, there are a number of good invoicing templates out there, some are even free like Starting Point from RCConsulting.com.
Your statement that you just want to keep using your old invoicing system but don't want to have to relearn FileMaker doesn't mean you can't upgrade.
You could migrate the old file to the new version (finding someone with an intermediary version to step it up from 3 to 7 then on to 12/13) and it should be essentially unchanged in appearance and behavior (depending on how it looked originally) if you migrate the file rather than rebuild it from scratch.
I suggest contacting a FMI sales person to explain your situation to be sure a migration of your existing file from 3 to 13 gets handled correctly, and then just keep using it. You can gradually dip your toe into the pool of new goodies if you want, or keep plugging away at the old appearance and behavior with hardly any visible change.