First off, I'd boot from the CD to install, much faster! OK, that's out of the way. 
Did you try booting with a DOS floppy, and see if you can FDISK the hard disk? It sounds like when Windows starts to access the hard disk, it chokes.
Did you try booting with a DOS floppy, and see if you can FDISK the hard disk? It sounds like when Windows starts to access the hard disk, it chokes.