taizoon.
Don't know the specs on your Sony Plasma, but some displays are fussy about their native resolution. Have you checked compatibility with the DVD player. You might need to change the default on your display for DVD source.

Whenever I had noise (electrical) interferance on my old CRT, it appeared as minuet horizantial bands in red and blue crackalin away.
Have not ever seen this on my LCD, but have noticed a hugh diffrence between component cable quality.