Good ol crv satnav again!?

I have a 2006 CRV which when I bought it had a Disc error problem (was promised new DVD to supposedly fix it) I discovered the head cleaning fix which worked.
HOWEVER, now I have a different problem.
At start up it worked fine until I turn the igntion further to start the engine. At this point the screen goes blank and I am left with just the radio station previously selected, vol and on/off nothing else works. Any ideas?

Mike fm Derbyshire
June 2011