count yourself lucky they can get to you by saturday pal. the HDMI packed up on my 3 month old box and they said i would have to wait 9 days as they were busy!!!! 9 days without a service you pay top whack for.
i sent an email to the chief executive that night and someone was out to replace with a new box the day after!!
as fella said above leave off out of mains for 5 mins then power up. if still not working leave on stand by then hold the power button down till you see the lights change colour.

hth

norton