In ubuntu 8.10 or 9.04 they introduced a different way of setting the
screen resolution. One had to use randr which has now been replaced by
grandr.

I've just tried ubuntu 9.10 and it works fine. However, it seems
ubuntu is using a few more resources and running a bit slow on my
machine - so i thought i'd switch to xubuntu and now can't set up
screen resolution of 1024 x 768. [i've used 1024 x 768 for so long all
my wallpaper and such is set up for it].