hi i have a problem with changing resolution on my machine and need some help.

i have a packard bell 1015 monitor and the graphics card is a NVIDIA Geforce2 MX 200 card.
the graphics card should easy allow for a screen resoluton of 1024x768 but i can only get 800x600 and 640 480.
iv installed new drivers for the card but they dont seem to do anything.
i dont know what the problem is?
is it the monitor that wont allow that resolution?