Software Update lost my channels??

I have a daewoo DLP-37C3 flat screen TV, Today I did a software update as I thought it would retune the freeview channels in...BUT I have lost everything, I change to mono and auto tune & manual tune - nothing just snowy picture through out search.
I can not get back into the DVB menu where I updated from the screen just goes black when I select it now.
Please any help would be truely appericated...many thanks