This was the situation I had with the initial install but pretty soon
it offered me the use of two proprietary drivers from Nvidia- once
installed I had my normal resolution options back. Check to see if
you are allowing nonfree software. This is the only way you will
get those proprietary drivers.

In kernel version 2.6.28, the kernel used in Ubuntu 9.04, the Graphics
Execution Manager (GEM) has migrated to the kernel. This should simplify and
improve the efficiency of X Server memory management, but requires some
changes to graphics drivers.

As a result old drivers will not work. This is a short term problem that
only affects those with kernel 2.6.28 and up and as new drivers are written
they will include this feature. That is not much good in your situation. If
you did an upgrade as opposed to fresh installation, try running the older
kernel which should still be in your grub list. If you did a fresh
installation search for a new driver from Nvidia or compile your own.

I've gotten nowhere with 9.04 on my Dell Dimension 2400 with integrated Intel
82845 graphics - booting the live CD in either "Normal" or "Safe Graphics" mode.
Blank screen. It boots up completely - I get the expected sound effects, and I
can shut it down with <CTL><Alt><Delete>, followed by <Enter>.

I understand that support for integrated Intel graphics is a known deficiency
with 9.04 (and 8.10, I think). But it's rather disappointing, and I hope they
solve it before the end of LTS on 8.04.

No problems on my other Ubuntu box: a still-older Dell Dimension 4400, with an
Nvidia card.

It isn't an Ubuntu issue. It has to do with the new kernel 2.6.28 and any
distro using it will have the same issues because the kernel now has a
graphics execution manager or GEM. This requires new drivers. Intel knew
this but dragged their heels in getting the drivers out. It may not be fixed
for some time. Ubuntu elected to go with this kernel because it added ext4
as well and kernel 2.6.29 is out but was not ready for inclusion. To stick
with last fall's kernel 2.6.27 when Ubuntu 9.04 is trying to move things
forward would have been silly.

Blame Intel if you feel like blaming anyone. The other graphics cards
manufacturers had the same timelines and they got theirs done.

If you did an upgrade instead of fresh installation, then try booting into
the older 2.6.27 kernel which should still be in your grub list or on your
computer.

How would one do this?....................

Yes have same thing so I'm stuck in 8.04. Can install 8.10 but have no special
effects. Hoping 9.04 would have solved it but just get a blank screen when it
was updated. So when this gets straightened out will use 8.04 for now. I have
three computers and have the same problem with all of them. Nice to know Intel
has yet to get a gait on.