Hello
You can try my solver at
http://www.tgmdev.be/isanaki_15b.php.
Enter the board (manually or from the clipboard) and switch to 'Solve Mode' by using the menu 'Sudoku | Solve'.
As far as I test it, it always found the solution(s). If Isanaki finds more than one solution, it gives you the number of solutions found...
For the following board,
5.34.....
....58...
......8..
.......9.
......4..
....6....
..4......
.2...1...
1........
Isanaki 1.5b found 526 solutions (when switching from SET to SOLVE)
Thierry