Ok now I am stuck... after days of good results I have a puzzle that I am stuck on.

All the tiles are in order except for 2...
right now my 11 and 12 are reversed....
I can change which two are reversed
but can't get rid of having 2 tiles reversed.
is this fixable or is it a fix-it ticket?

Thank you

Every position that's legal, and that is every one that the game provides you, is solvable.
try http://www.brian-borowski.com/Software/Puzzle/

There are a whole set of positions that are unsolvable, but the game never gives you one of those. But interestingly enough the game does display one of those in the puzzle before you start it.

But if you want to fix your situation without that java app then recheck every row from the top and undo anything below if necessary. Because if you think you have 1,2,3,4 but don't and have perhaps 1,3,2,4 then it's wrong.

Or as a cool experiment try to get to the following position, which the game says is 'solved'.

1 2 3 4
5 6 7 8
9 10 11 0
13 12 14 15

Rebecca, I did that once, also. Because the 2 and 3 are so similar, I didn't notice it for 2 days and was going nuts trying to solve it!