TECHNIKA 32" TV SWITCHES ITSEFLL OFF?

I Have 1 32" TV from tescos connected to SKY+ HD box via the HDMI 1 Slot. Also connected is a DVD/VCR combo via the SCART1 Socket.
Problem is that the screen on the TV will turn blue, and you have to switch the TV to standby via the remote control and back on again for anything to work. I have spoken to TESCO in the past but all they do is ask you to unplug telephones etc and wait around and switch the thing back on. Its alright for them as i am paying for the phone call.

The problem is sporadic and i don't think that it is an over-heating problem.

Any help / ideas would be greayly appreciated.