From: Andrew Sackville-West on
On Fri, Sep 04, 2009 at 05:01:16AM -0400, Spam Catcher wrote:
> Version: Debian 5.0.2a-i386
>
> The Bug: Computer goes to sleep during the boot process.
>
> During the initial boot, after the setup text has scrolled down the screen and just before the logon
> screen should appear, I receive the message:
>
> UNKNOWN MODE
> H 74.9KHZ V 59.9HZ
> GOING TO SLEEP

this is almost certainly a message from the *monitor* and not from the
*computer*. The X window system has selected a configuration that does
not work with the monitor and the monitor, not recieving a usable
signal just goes to sleep.

as a starting point, try Ctrl-Alt-F1 to get to a virtual
terminal. Assuming that works, you can log in to the console and fix
it up from there.

hth,

A