You got Debian, a 3Com Corporation 3c905C-TX/TX-M [Tornado] (rev 74) Ethernet controller and a PC which needs to be started via LAN and it is not working?

I assume you change the BIOS settings already. All you need to do now, is to tell you Debian not to turn off your Ethernet controller while shutting down your system.

Create a new file /etc/modprobe.d/3c59x and add following line:

and run

Now you are done.
I use wakeonlan to start my computers.