Please download the new Aly-Sudoku 2012 from the link below.
With the help of it you can solve the most sudokus within seconds
and the difficult sudokus within minutes!
It works under:
Microsoft Excel ($),
OpenOffice (free),
LibreOffice(free).
http://alybadix.wippiespace.com/sudo.htm
Ps.
Surely virusfree!