Cannot download any pdf file

I cannot download any pdf file onto my computer.  I can view the file, but cannot download. When I try download the usual screen comes up asking whether I want to run or save the file.  I always click run and the download starts, but then the message comes up saying access denied.  I cannot print in the view mode or save onto my computer.  I used to be able to do this, but not I'm not able to with any pdf file, so there is no one corrupted file.  I receive many pdf files, so this is very irritating.  There is something wrong with my computer, but I have no idea.  Any help would be greatly appreciated