If you are desperate, you should be able to build from source. Versions of the source code go right back to 2011 v0.1.14
Windows executables and installers go back to 2011 as well.
You might, as Dave say’s, need to find a matching version of Node-RED though. Try v4.8.7 first though: https://nodejs.org/download/release/v4.8.7/ the x86 version should work.
Whatever you do however, make ABSOLUTELY certain that:
- The machine has no route to the Internet
- If at all possible, turn off file & print sharing on the device & disable NTLM v1 (Wannacry and other exploits)
This means that you will have to manually download any nodes (and software updates) you want to install. Do not let the PC do automatic updates. (It is possible to have an intermediary update proxy for some software updates but this would require some level of enterprise infrastructure).
Be very careful what you allow the PC to do. It is very vulnerable.