Nav gone into default mode how to re-install?

[barflux]

I updated my car back in Nov 05 with v26 and tried to do my friends and the screen stayed black for 10mins on his X5 and has now gone into default mode. I think my disc is no good.

How do you to install the Nav Firmware when the system is in default mode?

As the instructions say go into GPS then take the NAV DVD out and then you put the firmware dvd

I have got hold of another copy and wanted to confirm:

I put the Firmware CD first then turn ignition to first point and the see the on-screen instruction? Or is there a special way?

(MKIV DVD based on a X5)