I kept the Windows sounds on, and got rid of the true duplicate non-Windows sound files. Windows stays intact. Weirdly, I found some 0 byte files (all non-Windows) which went in the recycle bin, and most recovered the data (PC by itself) when they went into the Recyle Bin. However, I have seen threads that files start tymurning 0 bytes and the PC goes, so backing up most important now. Freed up 4 GB space, by the way.