I have sound but no picture,also when i turn the television off I get the light flash aross the screen that I usually get when I shut the power off and when I turn it back on I still have no picture only sound.

Jennifer Taylor, June 2005

It probably has frame collapse and the TV is blanking the picture out to protect the cathode ray tube.

If that's the case, you will need an engineer to fix it.
On the bright side, frame collapse repairs are usually straightforward to correct & towards the cheaper end of TV repair costs.

Cobweb, June 2005