It looks like you are still running on the generic VGA driver instead of the
updated NVIDIA driver.
You can use device manager to see if this is the case.
Given that the monitor may not be detected properly, or the situation I
mentioned are possible, I suggest that you see if the Nvidia "control panel"
choice exists
when you right click on the desk top background (not on an icon.) This may
also indicate which drivers are active. In the Nvidia control panel, (Nvidia
drivers active) you should have an option to change display resolution.
Normally the generic VGA/SVGA driver allows you to choose something greater
than 640x480.
If the Nvidia driver failed to install properly, you may need to use "safe
mode" to revert to the generic video driver, run a "cleanup utility or
process from Nvidia, and redownload & install the correct driver.
Since you did not identify the Nvidia based video card or chip set, more
specific instructions for your hardware may be found on the Nvidia web site,
or the card mfrs web site. Some video cards have features unique to the
mfrs cards, and may require custom versions of the drivers, rather than the
Nvidia generic drivers.