Here's a possible solution that member Richard Daly emailed to the mods:
The answer that worked for me was to use the DEL command in Windows Command Prompt, but to give it a slightly different parameter than the original poster, fantasticness, tried. Specifically, in Windows Command Prompt, from the path C:\Users\USERNAME\Desktop\ I ran the command
del "\\?\C:\Users\USERNAME\Desktop\[the entire ~255 character filename here].pdf"
The quotation marks are part of the command, the square brackets and the description inside them are not.