I use Mandrake 9.0, and the way I did it was edit a line in /etc/inittab, where it read
I changed it to read
Read any comments above this line, yours may be different. Whatever you do, don't put in the number corresponding with "reboot", as the system will constantly reboot, requiring a start with your Linux emergency boot disc and a re-editing of the /etc/inittab file.
If you do it right, you'll wind up in console mode, just log in there.