fail to install sql server 2005 express eddision for navision 2009 r2

[:(]

please describ in detail what you have done and which error messages were shown.

what failed? the nav 2009 install or the sql express install?

Why would you be installing SQL 2005 with NAV 2009 R2? Microsoft stopped supporting SQL 2005 well before NAV 2009 R2 was released.