I have been using an Acer laptop on a Panasonic tv using a monitor cable and audio via 3.5mm to 2 RCA cable with no problems until recently when the picture on the tv went blank, but laptop display was fine. Have done a bit of troubleshooting and found

1) the laptop displays ok on a standard desktop monitor using the same cable or the desktop computer's cable
2) the desktop computer displays ok on the tv using either cable
3) laptop has the same issue with either cable. When laptop is connected to the tv there are a few options available
in H & V sync mode the H-freq and V-freq show as 0, but in SOG mode the picture does show but the colours are all distorted.  H-freq and V-freq have values

I thought that swapping cables eliminates a cable problem, connecting laptop to standard monitor eliminates the laptop problem and connecting the desktop to the tv eliminates a tv problem! Any ideas what is wrong?

Thanks