Can anyone help please. Switched my NEC Plasma tv on yesterday and a blue vertical line has appeared on it, just 1 pixel wide from top to bottom. the line changes colour a bit, like it displays white background ok but stands out blue on green background.

Anyone any idea if this is a big problem, like whole screen bad, or maybe just a small component problem?

Also does anyone know anyone who can help?

It almost certainly requires the Plasma panel replacing, it's a VERY common failure on PDP's. The actual fault 'may' be on one of the panels fitted to the PDP, but these are usually an integral part of it.

Mostly though it's probably to do with the way the connections are bonded to the panel itself.

Oh S**t, that sounds very expensive!

Is replacing panels cost effective - and where can they be sourced from?

No it's not, it usually costs more than the TV did originally (assuming they are even available?).