Bought a now TV black box from tesco last Tuesday,, has worked fine and not had a problem until today!! Went to switch it on and it has cone up on the TV saying "unknown video format" can anyone help starting to annoy me now can't figure it out tried on a diff TV and says same!!
Thanks for posting. I'd go for resetting the box by putting a pin or paperclip in the hole at the back and holding it there for 10s or so. Also, if you've not already, if possible try a different HDMI lead.
Hopefully this will sort the problem, if not please re-post and a member of the NOW TV Team/forum member will get you up and running