Nvidia Clone display problem

[Granty]

Hi, I have connected my PC to my Daewoo plasma TV (Tuner box) by Scart and also tried S-Vid but the display was only clear during the initial loadup and as soon as windows loads it just loses the pic, sometimes it scrolls with desktop visible, I tried all resolutions and all settings and come to the conclusion that the problem is my Nvidia 6700 XL card as when I delete the drivers and go to standard VGA it works perfect, The strange thing is I can load the basic drivers of Nvid and it will work after a re-start in any res I like but usually the next time I come to PC after restarting again it is scrolling again and nothing but uninstalling the drivers seems to fix it, The newest drivers available for my card are absolutely useless as it will only display HDTV as my PC has HD output on it, but my TV is not HD, and when I tell it I am using scart or composite it will not change from HDTV, but the older drivers on my original CD are fine with understanding the connection, but I cannot maintain a stable picture, anybody any ideas I have been through all settings and spent hours trying to sort it, Could the card be faulty? Could memory be an issue as I know I have 1 GB Ram but for some reason the new software struggles during the 15 second preview which has took about 30 seconds before while changing to different resolutions and the computer is pretty much frozen while struggling between them, only when trying to transmit the extra pic to my TV though, otherwise it seems ok , any help or ideas appreciated - Thanks