e-mail attachments

A relative of mine sends me e-mails with attachments, I am having difficulty opening them, I have Powerpoint 2007 and excel 2003, but these will not open them, I sent an e-mail asking which program created them, and was told Media Player 6 would work, I have Media Player 11, that will not work either, the attachment states that it is a ‘File Extension E-mail. any idea has to which program will work. Yours John B