I'm still at a loss why your data would be missing... and why a rather large amount of data is remaining. There isn't any way that I can think of that Linux could have caused that, not even if the drive were attached when you installed Linux. It would have been either totally erased or totally left alone unless you had done a custom partitioning, which I'm fairly sure you didn't, and the drive wasn't attached anyway so that is a non-issue.
You found all your folders, but they seem to be empty. That keeps bugging me. Neither Windows nor Linux would do a "random destruction" of data. I really want to think that the files are there, and that Linux is failing to see them. But I can't think of what mechanism might do that, except maybe encryption. The most simple and common encryption used with Windows is called Bit Locker, but I think it encrypts the whole drive, and you would have had to enter a password every time the computer booted, even before Windows started. (Let me know if that is the case!) Other programs can encrypt just files or folders, but I doubt you would have done that either.
If you want to investigate a little more, mount the Windows drive again, and browse to your folders. Right-click on a folder, then left-click to choose Properties for that folder. This will report how many files are inside and how much storage space they use in bytes, KB, MB, or GB. So it may report zero files, if empty. But if it says there are some number there, and if you double-click the folder to open it and see none, then that would be interesting. Also, while looking, right-click and look at Properties for other folders until you see where the the bulk of that 150GB of stuff is, and then look around inside and see what that might be.
If, by some strange case, you look at Properties and see a number of files, but double-clicking the folder doesn't show them.... try to right-click on the folder, choose Copy, then come back to your Mint desktop, and right-click on an empty spot and choose Paste. Of course the hope would be that you could then actually see the files after they're pasted into Linux.
And I'll keep looking for other things that might explain what's going on.
Cheers!