It might be a good idea in the future to post a little more info on what a program does rather than expecting someone here to do it for you. I'd never heard of djvu and chm. After looking up what they are, I've now read about it but don't care. If you just googled it you probably would have found a site like the one below:
can someone assist before i return to windows
Feel free to go anytime, I doubt anyone here will lose sleep over it and certainly not money.