nvidia problems after upgrade

[Aidan Gauland <wgsilkie@ihug.co.nz>]

Hello,

 I just upgraded to lenny without any problems, except for one: I'm using the 
vesa xorg driver, because using the free nv driver causes the display to 
freeze after a few minutes of use (I can move the mouse, but I can't even 
switch to a virtual console).  I was using the non-free nvidia driver before 
the upgrade, but after upgrading, X wouldn't start until after I ran...

"dpkg-reconfigure xserver-xorg"

...and added the following lines to /etc/X11/xorg.conf...

SubSection "Display"
        Depth           24
        Modes           "1280x1024" "1152x864" "1024x768" "800x600" "640x480"
EndSubSection

...(before I added that subsection, my monitor gave the "out of range" message 
when X started).

 I want to be able to use the free nv driver (without problems) before I even 
try to get the non-free dirver working.  I'm really stumped here; can anyone 
help?  (By the way, this is the first time I've upgraded a Debian system.)

Thanks,
Aidan