I deleted my InDesign files because I deleted all the user files of mine. Everything.
With a recovery software I found the files again. But they cannot be opened. What can I do?
Surely all the files can't be broken. One, two, but not all. Can't they?
I use CS.
I'm too excited. I use CS3. Sorry.
Do the files still have the .indd extension?
And are you trying to open them with a newer version than the version they were created in? That's important, especially with the older versions you mention.
No, I only have the CS3 version.
So, are these InDesign files newer than CS3? Just want to be clear on that. If they are CS3 or earlier, then they are, as Bob menioned, the files could be hopelessly corrupted. Happy to try to open one with an earlier version just to test, but that's not going to solve your overall problem.
Surely, and quite sadly, they can.
The best advice I can give you is for the future only. Let this be a lesson to always have a backup plan. I Always work in a Dropbox or OneDrive folder where restoration of deleted files is only a mouse click away. I suggest you do the same.
There's one thing you need to know - Adobe turned off the activation server for CS3. That means you CANNOT activate the software at all. You can probably keep using it on the same computer, but if the computer breaks or you upgrade the computer that is the end of CS3 for you. Trying to fix CS3 problems by reinstalling is very high risk indeed. Adobe will be very happy for you to take out a CC subscription, of course.