Applications :: .pdf Files Open As Blank Pages?

i have recently been having trouble opening .pdf files properly. they open but they are all blank pages. they open as blank files in "preview", it doesnt open at all using adobe digital additions and through microsoft word i get gibberish or i get pop ups that say "word cannot open this document. the document might be in use or might not be a valid word document" ive downloaded over 5 times and each time i try with all three options and i get the same thing.

i tried to pull it into iArchiver but that also didnt work.

the file ends with .pdf

also although several other documents have done the same thing i know something is not completely wrong with my .pdf thing or any of those applications because other pdf files do open.

i tried to give as much information right at the beginning so forgive me if its too long.