Problem changing monitor

[Gerald I. Evenden]

I am running Hardy on a Dell which originally had a 2001FP monitor with a 
resolution of 1280x1024. That monitor that died some time ago and I replaced 
it with a Dell ST2210 which has a 1920x1080 resolution.

The problem is that the current displayed screen is still at the 1280x1024 and 
does not fill the screen horizontally and the "Systems Setting" 
program "Monitor&display option" does not allow me to select the higher 
resolution.

Question: is there any way to fix this problem and allow full screen use of 
the ST2210 monitor's screen size?

Many thanks in advance.

-- 
"Religion is regarded by the common people as true,
by the wise as false, and by rulers as useful." --- Seneca