Keylogging - .imh extension files

Hi I'm wondering if any of you can possibly help me. I downloaded a basic keylogging package from ZDnet. I have located the folder on the pc that has the files that are hidden, I've managed to unhide them but I don't know how to read them. I've tried with notepad, word and excel. Can someone please advise me how I can read them or there is no point in having it there. I emailed ZDnet support, the referred me to Incredimail. I emailed them and they referred me back to ZDnet. Please please can someone help me check what the kids are doing when I'm not around. Thanks very much