Some possibilities:
- The files are actualy encrypted.
You need to provide the correct password/decryption key. I can't help you on that point.
The creator of the encrypted file may be able to provide you the correct password/decryption key.
- The files are compressed and you try to open them before they are uncompressed.
Get some archival utility, like isarc or power archiver (both universal and free archival utilities), and extract the actual files from the archive.
- You are trying to open the files with an application that don't understand the format used, like using notepad to open an exel spread sheet or some picture.
The computer you are using may not have the required application needed to open those files. Install the appropriate application and try again.
Make sure that your files associations are correct.
- The file may actualy have the wrong extention.
Look if you can restore the original extention.
Some application may actualy find that the extention is wrong and offer to correct the problem for you.
- The files may be corrupted.
The data from corrupted files are usualy lost for ever unless you can find some other copy of it.
Electro, November 2012