I think you got bad advice from somebody that just couldnt figure out what to do. qb 2013 is supported on vista. I havent looked up whether 2010 works on win 7 but i suspect it does. By "not supported" they just mean that they wont help you with it or fix it anymore. Not that it shouldnt run.
I am out for the morning but i can talk to you this afternoon.
if the qb used to work recently on that computer you might try doing a system restore to when it was working
SYSTEM RESTORE INSTRUCTIONS - XP VISTA
start menu / all programs / accessories / system tools / system restore
select restore to an earlier date
you will get a calendar with various restore points for each day
choose one for a date BEFORE the problem started
hit the ok /restore button
the system will start to shut itself down and a blue status line will come up in a box saying restoring your system settings.
when it finishes the system will restart itself.
hopefully everything will work the way it did on the date you selected