because its not supported by your current monitor. http://www.nvidia.com/object/geforce6_techspecs.html
according to nvidia, you gpu falls under the Geforce 6 category. So it supports up to 2048 × 1536 at 85Hz
according to nvidia, you gpu falls under the Geforce 6 category. So it supports up to 2048 × 1536 at 85Hz
