Why won't my tv's picture come on?

I have an LCD 42" LG tv, the picture won't come on but I see it's getting power as there is a dull purple hue. No sound either. The power light blinks when it comes on (it used to go to a solid green) but I get nothing. Once played with the power cord and heard a bleep and it came on and then went dark again. Could it simply be the power cord?