The screenshot is only taken/shown in the save or load windows when Full Screen Anti-Aliasing is disabled. If you enabled FSAA after that crash, try running the configuration program and setting FSAA to mode 0, then hit the 'apply & close' button. There is a display issue with the configuration program always showing the FSAA mode as zero when first opened, so try changing it, then change it back to zero and hit 'apply & close'.
You can delete saves from within the save and load windows (select the save game and hit the trashcan icon in the bottom left of the window).
Using Windows Explorer (or whatever) does allow you additional options, though (move, zip, etc). The default install folder for BD is 'C:\Program Files\Larian Studios\Beyond Divinity', so that is most likely where it is (if you changed the path during install, it would probably have been to a specific games folder or partition, which you would remember). You can also right click on the game shortcut (either in the start menu or on the desktop) and select Properties to show the path to the game.