Been forever since I had to do this, but if that resolution is listed as
available in your XF86Config file, then isn't there a key-combo - like
CTRL+/CTRL- or maybe a shift in there as well - that will toggle through
those listed available resolutions?

meg@leary.csoft.net wrote:
> 
> Check your XF86Config file ('/etc/X11/XF86Config')
> 
> On Sun, Dec 30, 2001 at 04:43:05PM -0700, Tom Achtenberg wrote:
> > I had to rebuild my system due to installing some bad software.  I used to be
> > at 1024X768 screen resolution.  Now I'm at 800X600.  How do I change it back?
> >  This is simple in Windows but I cannot find it in Linux.