Thanks first!

About corruption: in fact "lots" of corruption occurs, and I gess in most os the cases that's because of the networks and users...
We work with schools and usualy, even if the application works in 5-10 workstations the entire network is bigger.
When I talk on chanching to sqlexpress its because i think the database corrects itself when occurs unexpected shutdowns, crashs, networks flickers... is this realy true?

Thank's again
NPedro