changing resolution without screen

[Douglas Alves]

I didn't state my problem correctly:
Close to the end of the Warty installation and update, the OS changed from
text mode to graphical mode invoking a resolution that the monitor does not
support. So it (the monitor) has switched off!  I can't see anything. The
monitor won't function with 1600x1400 resolution, so I must tell the Warty
installation (or the xfree86 configuration) program to switch to 1024x780,
but that can only be done by typing on the keyboard, because the monitor
won't show anything and so the mouse is useless.

This is the first time I install Warty (and Linux). I used the complete
Warty i386 iso CD, and the installer connected to internet to download (apt)
updates. I want to know if after the resolution selection there is a
confirmation dialog box with which I can reject the selected resolution and
the installer will go back and ask for a valid resolution again, or if thru
a sequence of keys I can (by faith, not by sight) select a different
resolution.