If im not mistaken, windows 8 and windows 7 don't communicate well with each other on a network either. I had them on a home network and the windows 7 systems were unable to access shared directories and files on the windows 8 machines! A windows 8 system can read a windows7 shared directory however. I cant image simply swapping a hdd from a win8 system into a win7 system will allow that process to be any easier.
By the way, in addition to the above, im not sure that you can simply pull the master drive out of one computer and put into another completely different one with different specs and boot from it (you need to use it as a slave...ie a second drive only)! Windows normally doesn't allow that. There were ways around the issue, however I haven't successfully been able to do it in recent times...needs someone with more knowledge than myself to do it. other guys here will be able to help out with this one though.