As Granny suggested, first run an md5sum check on the iso. Unless it's good, it is not going to work.
The direct ISO method is not that hard, it's just less "automagic" than if you can boot from the CD. As described, copy the iso file to the root directory of a FAT32 partition. Extract the kernel, initrd and loadlin files to the same location. Boot to DOS, change to this drive and issue command:
loadlin.exe sata initrd=initrd.img load_ramdisk=1 ramdisk_size=18000 rw root=/dev/ramYou may need to edit the file names to match the ones you actually use.