I know this is easy for me to say because it is not my money I'm spending, but an upgrade of BIAB might be well overdue for you. I don't even have a clue as to how far back Version 10 was, but that is getting a bit old. New computer, new software. They kind of go together and I suspect that if you did upgrade to the latest version you would be impressed.
Re: Win 7 running the older files, you might try running them in compatibility mode. Best guess I can make.
Good luck.