I received a low disc space warning so I deleted about 10 GB of files (video and images) from the C: drive but it did not gain any free space. I rebooted and all the files I deleted had returned. The Recycle Bin is empty and I hold down the Ctrl key to delete the files directly. I did this a few times and the files always return. I even tried booting into safe mode, deleteing the files, and rebooting into safe mode again but the files keep coming back. What do I have to do to delete these files?