Any ideas....

My Sat Nav (X5) has just started to say that there is no disc in the drive.

I've bought a new disc in case it was damaged. Still the same message.

However, if I put in a software upgrade disc (my old v27 disc), it loads up as normal.

This would suggest the DVD unit is ok, but a bit confused as to why (now 3 different) Nav DVD's don't work.

I stuck !