Are you saying that you download a file from the internet, save it to some location, eg your Desktop as a good, temporary, location, then when the download is finished you find the file just downloaded, then click, (or double click depending on your own preferences), and the file doesn't open?
Is that what you mean? And if so, this is the same will all downloaded files?
Then the whole screen display starts flashing. How do you stop that?
Any error messages displayed?