google debian net-install...should be exactly what ya need
Or,install via debian based live cd like kanotix...which has three hdd install options....Debian like system(recommended)
beginner-mass hardware detection
kanotix install just like the cd(basically a copy cd to hard drive)
You should,considering you have plenty of space,be able to make a new partition and install debian there.The install will recognise your existing bootmanager.
Good luck