Do you have a second PC? It might be easier and more straightforward to simply put the old hard drive into a dock and connect it to another PC via USB.
And I second USAFRet's notion. Whether this story has a happy or sad ending, please make sure to have a proper backup regimen in the future; it's important basic upkeep that comes with PC ownership! it's always important, but doubly so when it's business-related stuff rather than personal things. I have a lot of peace of mind because when I'm doing some data consulting, anything I save in my work folder is instantly sent to both my backup server and the cloud.