Help with running a mac through a tv

I used to have a HDTV until it packed up and i used to run my mac through it no problem with a mini dvi to hdmi cable, since using my old tv which is lcd i bought a mini dvi to vga cable, only trouble is when using it is that there seems to be a black line at the left hand side of the screen as if the screen is not centered, i just wondered if anyone has any advice about this, is it the cable that has a fault or the tv?

Please refer to our Sticky Notice: How to connect your Mac to a TV