xbmcbuntb possible to reduce resolution?
 

ok I know in a world of high def this is a completely off the wall request but I need it.
I have xbmcbuntu booting off a usb 3.0
its in an old Dell
with 2 gigs ddr2
gt 430 and a C2D e6400 cpu

I have it connected to an old mitsubishi rear projection tv (it does show up as amonitorI got from goodwill using a DVI cable.
Problem is even at the lowest resolution I set 640x480 most of the useful stuff on the desktop is off the screen and I can't get to it.
In xbmc, about a third of the video is off the screen unless i use window mode.

I would like to know if I can shrink the output to a 16:9 480x250ish so I can see everything on the desktop
and if so how? 'm sure there has to be a .config I can edit somewhere.
I've finally convinced my wife to try xbmc on the other tv and I really don't want to hear her critique.

If you know howplease give me foolproof instructions. I can adjust the resolution bit by bit till I get it right.

Thank you all.

maybe this will do it http://ubuntuforums.org/showthread.php?t=1346125