Considering how old that monitor is there isn't much info out there on it. What little I can find is this from back in 2004, Get me outta 60hz!
PX-769N is a Proview 769N
PX-769N 17" 0.27mm / 1280x1024@65 / TCO99 / VIEWABLE AREA 15,70" / HOR.FREQ: 30-70KHz / VERT.FREQ: 50-160Hz / DOT RATE 110MHz / 1024 x 768@85Hz / 800 x 600@110Hz / OSD / MPRII / TUV / CE / UL / CUL /
Max supported resolution of 1280x1024@65Hz. Not sure how you managed to get it to run at 1440x900.
Also even if you did manage to find a driver
for it, Anyone know of CRT monitor drivers? (product info in thread)
it still won't allow you to run it at 1440x900