Finally! We tried all the suggestions we were given from my post last night. Still only gained another couple of % of hard disk space. I KNEW there were backups of programs we'd uninstalled somewhere but we just could find where! We've been looking and searching to find where they were stored for 2+ weeks.
After deleting all the backups that were in there, we now have 50% hard disk space! yay!!! I can install my new QuickbooksPro and my new Mary Kay software!
And, on that note, I'm calling it a day! Good night everyone. And thanks again for all the suggestions!