I have just tried using the network install disk (and a full DVD) and neither of them seems to start up the graphics correctly on my old PC, so after a bit of research, it turns out I can set the installer to run in text mode rather than graphics mode by changing:

vmlinuz initrd=initrd.img

to

vmlinuz initrd=initrd.img text

when starting up the installer. Then, it will run in text mode, and even offer the option of using VNC to remotely configure. Screenshot: