Someone PLEASE answer our posts. I had the exact same thing happen this week. 25-40 year old tiles stuck down with tar (over a pine subfloor)that my wife decided to try to remove with a heat gun and scraper. Is there any easier way? Her method only succeded in messing up the existing floor, so that we can't put anything on top of it.

There is a reason that the second layer of tile was placed over the original and you have discovered that reason. There is no easy
way of removing floor tile other than using a hair dryer or heat lamp to soften the adhesive. If you decide to go this route, you then have the thankless task of removing all of the adhesive from the floor. The quickest and easiest way is to bite the bullet and remove the whole floor. If you are planning to reinstall tile then 3/4" plywood can be used since asthetics is of no concern.
GOOD LUCK!!!!

Have you tried renting and electric tile stripper!?