Well, i know when i set my TV up as the secondary monitor (its an old shitty TV, not HD ready) I can use the ATI control pannel (im sure nvidia have the same sort of options) to set it up right.
When i 1st pluged mine in, it was black and white but not flickery. I changed the colour easily in the ati options (NTSC to PAL, not so sure where, i clicked everything to find it)
But as for flickering off the bottom ofthe screen, i'm not 100% sure what you mean. Do you mean a flickering like a bug in a game or the mouse move out of the TV's view and moves the rest of the display move with it?
If its the mouse move, screen move scenario, then the screen rez for the TV is too large, if its the flickery like a bug, then i dont know. If anything, it should all be sortable in the gfx card's options, as it should be compatable of all regions and TV types.