ATI 9800XT WITH HDTV

I recently purchased a Sony 42" rear projection TV with 720p resolution
(best 1280 x 720). I also purchased a DVI to HDMI cable so I'm getting
direct video output to the monitor and not having to use the SVideo
which is more limited. However, I'm having some problems with the
display.

My main problem is that the left side of the desktop and bottom portion
of the taskbar are cut off from the screen. Because its a TV and not a
monitor you don't have the same move and shrink funtions built into the
TV as you do with a monitor to reposition the screen output. The TV
does have a -1 or +1 shrink zoom function but that doens't fix the
problem. Is there any way to move or shrink the screen display with
software?

Also I tested with two computers and three video cards. 1 = ATI Radeon
9800XT, NVIDIA FX 5600, NVIDIA Ti 5000. The two NVIDIA cards can't
output the to the screen at all. The Ti 5000 card will output a little
square (top left corner of the screen) and the FX 5600 won't output at
all. I prepped the system by lowering the resolution to 800 x 600 with
60Mhz freq. Are there any special trick to buying a video card that is
most compatible with this type of output?

Thanks!