I did much photoshopping on pictures, of which I can't remember the original. The originals are gone. Can I retrieve them still?
The odds are against it, if you didn't take care of your files then you really only have yourself to blame.
That said, there is a feature called "previous versions" in Windows which has been around for quite some time and, if enabled, may save your bacon provided system restore was/is configured correctly, which it may have been by default.