question on disappearing modules

I installed Vassal and then downloaded about 12 modules of games I had when I was a kid.
I played some of them over a few days but when I went back they are all gone from the
vassal program. I am doing something wrong on download?

Vassal can’t delete any modules from your hard drive, so the downloaded files are still there somewhere. Removing a module from Vassal simply deletes its entry in the Module Manager; it doesn’t delete the actual module file.

Did you possibly move them from the location to where you downloaded them? That would remove them from the Module Manager.

Do a search of your drive and they should turn up. Then you can just re-add them to Vassal (under File > Open Module).