Well of course obtain a new copy of the software
But this time use "Torrents", im assuming you downloaded your files from a "mirror" like filefront.com or bfupdates.com or the likes.
To use torrents you need a bittorrent client like "uTorrent" or "BitTorrent" (I use bittorrent)
Torrents are legal pieces of information used by bit-torrent clients to redirect where to download the file from.
I have never had a corrupted file from a torrent client, because the clients constantly check the files and can repair them.
In some cases downloading from torrents can be faster than a mirror.
When you are downloading the file, you are also uploading the file to other users called "Peers" so in a way you are helping other people by using torrents.
"Seeders" are people who already have the file and are dedicating themselves to uploading the file to other people, because you should always upload at least the same amount you download.
Like if I downloaded 1gb of a torrent, I should at least upload 1gb.
"Leachers" are people who downloaded the file without uploading as a seeder for a while.
Heres a screenshot of me downloading PR_setup1of2
As you can see, you can pause the file... delete it... or look at information about the file.
Torrents are much more reliable also.