Sreen Resolution Issue

[Tom]

I prepared a new HDD for an existing computer using Ubuntu 8.04 LTS. The
install went well with Screen resolution of 1269X1024. Two day ago, the
resolution shifted on start up to 800X600.  I invoked sudo
dpkg-reconfigure xserver-xorg and did the dialog thing but no joy there
was no listings for a higher resolution. I use the same rage 128 pro and
viewsonic monitor combo that another HDD uses with good high resolution.

What am I missing here...I get no option to select the graphics card or
monitor.  Do I need to find a file in synaptic to install that I missed
on the HDD install???

Thanks, and regards,

Tom