Can't convert pdf to word

I have tried several times to convert a scan of an old handbound book from my grandfather into a word doc with no success. At first I was getting timed-out errors and messages saying the file was lager than the 100mb cap limit, but I have since figured out how to compress and optimize the file in adobe to well under that limit while keeping decent quality. It still will not convert the pdf to word (subscrpition is paid for) on the web or in the application. It sits on the first page for several minustes trying to grab the text and never get beyind that. I've treid every help tip I can find. All I have to work with is the original 123 mb pdf and the compressed pdf.