if you have a /etc/xorg.conf see if you have something like this in it,
Code:
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "metamodes" "1440x900_60 +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
the _60 part is your refresh rate and you can lookup for in in windows what it should be for your monitor, most tft screens accept this _60 however.
If you don't have a xorg.conf you can create a default file by typing nvidia-xconfig as root or sudo.
Most systems don't need a explicit xorg.conf file and let ev-dev automaticly setup your system, however ev-dev can be wrong if your monitor does not give back the right EDID data to figure out your monitor timing. Once you have the metamodes set in this file the xorg server assumes these values and not the ones provided by ev-dev mechanism.