[zenexer]

I think you're out of luck. Hindsight is 20/20, but shouldn't their hardware and software requirements have come up long before you started development? How did you get to the point at which you were actively developing without knowing your target environment, especially if you're on premise?

At first I wrote a response suggesting a few ways you might be able to get it working on older versions of Windows, but they're just not feasible for anything prior to XP. Possible? Probably, but more work than rewriting everything, most likely.

You might be able to convince them to upgrade and virtualize their Windows 2000 programs--heck, you might even be able to get away with using DOSBox. That seems a lot more realistic than virtualizing Linux or a newer version of Windows on Windows 2000. But I wouldn't get your hopes up--anyone still on Windows 2000 is going to object heavily to upgrading; that's why they're still on Windows 2000. You can eliminate all the barriers for them and they still won't want to do it.

Edit: This might sound crazy, but have you looked into whether it's possible to make some changes to Electron to get it to run on Windows 2000? It's designed to be portable, so, in theory, you should be able to get it to run on a potato--assuming said potato has enough RAM.

[Azeralthefallen]

Honestly we told them our requirements well over a year ago. Which wasn't an issue apparently, even when we did a pilot in their internal labs which they were running Ubuntu.

It only came up after we started the rollout, when someone from their side who was asked to write documentation about how our app would work into their workflow, realized our app didn't work at all on his station. Which lead to oh no their requirements are horribly wrong.

To me it was a communication breakdown on both sides, but i doubt i can get them to change.

I am going to give getting electron built in Virtual Box and see if i have any luck with it.

[zenexer]

I don't think you're going to be able to go the virtualization route with Windows 2000 as the host. As the client, sure, but not as the host. You'd need at least XP.

For many contractors, Windows 2000 as a requirement would be a red flag--decline the contract and run the other way, because that's just where it starts. Chances are you're looking at the tip of the iceberg.

Since you're already committed, though, your focus should probably be on pushing them to upgrade whatever they can. It's a lot easier to run old software on new platforms than the other way around. Whatever ancient programs they want to run, they can do it on newer versions of Windows--there's guaranteed to be a way, and it'll be a lot easier than getting a modern application running on Windows 2000. Lots of people want to run old programs on new computers. Nobody wants to run new programs on old computers.

Edit: To clarify, there are great programs like DOSBox that will let you run old programs you wouldn't normally be able to run on new versions of Windows. DOSBox targets a specific niche, but it works well, and the concept is quite prevalent: people want a way to run their old programs, even if it's just for nostalgia. I would bet my life on it being significantly easier to run their specialized software on a newer version of Windows, even if it's in a VM. (Or, heck, what about WINE, since they have Ubuntu?)