File disappeared?

I tried to download a file today from webmail/browser and hadn't realize that you had to set the file path in the preferences, so it began downloading onto the desktop. I moved the "downloading" icon into the folder where the file would go. It appeared to completely download in the Safari download menu, but gave the notice "can't be moved." I opened the folder that the file was going into, and it was still there in the download menu, but only partially downloaded. I deleted the partial download from the folder, and checked with spotlight. The file was nowhere to be found. However, I still appear to be missing harddrive space (it was a powerpoint presentation of an extremely large size). Could the file just be floating inaccessibly in my hardrive, taking up space, with no graphic representation in any folder of OS?